add sabre (1.8.x) via composer in the !@#$ place it wants to be

28 files changed, 5398 insertions, 0 deletions

diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component.php
new file mode 100644
index 000000000..1c1d92444
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component.php
@@ -0,0 +1,405 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VObject Component
+ *
+ * This class represents a VCALENDAR/VCARD component. A component is for example
+ * VEVENT, VTODO and also VCALENDAR. It starts with BEGIN:COMPONENTNAME and
+ * ends with END:COMPONENTNAME
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Component extends Node {
+
+    /**
+     * Name, for example VEVENT
+     *
+     * @var string
+     */
+    public $name;
+
+    /**
+     * Children properties and components
+     *
+     * @var array
+     */
+    public $children = array();
+
+    /**
+     * If components are added to this map, they will be automatically mapped
+     * to their respective classes, if parsed by the reader or constructed with
+     * the 'create' method.
+     *
+     * @var array
+     */
+    static public $classMap = array(
+        'VALARM'        => 'Sabre\\VObject\\Component\\VAlarm',
+        'VCALENDAR'     => 'Sabre\\VObject\\Component\\VCalendar',
+        'VCARD'         => 'Sabre\\VObject\\Component\\VCard',
+        'VEVENT'        => 'Sabre\\VObject\\Component\\VEvent',
+        'VJOURNAL'      => 'Sabre\\VObject\\Component\\VJournal',
+        'VTODO'         => 'Sabre\\VObject\\Component\\VTodo',
+        'VFREEBUSY'     => 'Sabre\\VObject\\Component\\VFreeBusy',
+    );
+
+    /**
+     * Creates the new component by name, but in addition will also see if
+     * there's a class mapped to the property name.
+     *
+     * @param string $name
+     * @param string $value
+     * @return Component
+     */
+    static public function create($name, $value = null) {
+
+        $name = strtoupper($name);
+
+        if (isset(self::$classMap[$name])) {
+            return new self::$classMap[$name]($name, $value);
+        } else {
+            return new self($name, $value);
+        }
+
+    }
+
+    /**
+     * Creates a new component.
+     *
+     * By default this object will iterate over its own children, but this can
+     * be overridden with the iterator argument
+     *
+     * @param string $name
+     * @param ElementList $iterator
+     */
+    public function __construct($name, ElementList $iterator = null) {
+
+        $this->name = strtoupper($name);
+        if (!is_null($iterator)) $this->iterator = $iterator;
+
+    }
+
+    /**
+     * Turns the object back into a serialized blob.
+     *
+     * @return string
+     */
+    public function serialize() {
+
+        $str = "BEGIN:" . $this->name . "\r\n";
+
+        /**
+         * Gives a component a 'score' for sorting purposes.
+         *
+         * This is solely used by the childrenSort method.
+         *
+         * A higher score means the item will be lower in the list.
+         * To avoid score collisions, each "score category" has a reasonable
+         * space to accomodate elements. The $key is added to the $score to
+         * preserve the original relative order of elements.
+         *
+         * @param int $key
+         * @param array $array
+         * @return int
+         */
+        $sortScore = function($key, $array) {
+
+            if ($array[$key] instanceof Component) {
+
+                // We want to encode VTIMEZONE first, this is a personal
+                // preference.
+                if ($array[$key]->name === 'VTIMEZONE') {
+                    $score=300000000;
+                    return $score+$key;
+                } else {
+                    $score=400000000;
+                    return $score+$key;
+                }
+            } else {
+                // Properties get encoded first
+                // VCARD version 4.0 wants the VERSION property to appear first
+                if ($array[$key] instanceof Property) {
+                    if ($array[$key]->name === 'VERSION') {
+                        $score=100000000;
+                        return $score+$key;
+                    } else {
+                        // All other properties
+                        $score=200000000;
+                        return $score+$key;
+                    }
+                }
+            }
+
+        };
+
+        $tmp = $this->children;
+        uksort($this->children, function($a, $b) use ($sortScore, $tmp) {
+
+            $sA = $sortScore($a, $tmp);
+            $sB = $sortScore($b, $tmp);
+
+            if ($sA === $sB) return 0;
+
+            return ($sA < $sB) ? -1 : 1;
+
+        });
+
+        foreach($this->children as $child) $str.=$child->serialize();
+        $str.= "END:" . $this->name . "\r\n";
+
+        return $str;
+
+    }
+
+    /**
+     * Adds a new component or element
+     *
+     * You can call this method with the following syntaxes:
+     *
+     * add(Node $node)
+     * add(string $name, $value, array $parameters = array())
+     *
+     * The first version adds an Element
+     * The second adds a property as a string.
+     *
+     * @param mixed $item
+     * @param mixed $itemValue
+     * @return void
+     */
+    public function add($item, $itemValue = null, array $parameters = array()) {
+
+        if ($item instanceof Node) {
+            if (!is_null($itemValue)) {
+                throw new \InvalidArgumentException('The second argument must not be specified, when passing a VObject Node');
+            }
+            $item->parent = $this;
+            $this->children[] = $item;
+        } elseif(is_string($item)) {
+
+            $item = Property::create($item,$itemValue, $parameters);
+            $item->parent = $this;
+            $this->children[] = $item;
+
+        } else {
+
+            throw new \InvalidArgumentException('The first argument must either be a \\Sabre\\VObject\\Node or a string');
+
+        }
+
+    }
+
+    /**
+     * Returns an iterable list of children
+     *
+     * @return ElementList
+     */
+    public function children() {
+
+        return new ElementList($this->children);
+
+    }
+
+    /**
+     * Returns an array with elements that match the specified name.
+     *
+     * This function is also aware of MIME-Directory groups (as they appear in
+     * vcards). This means that if a property is grouped as "HOME.EMAIL", it
+     * will also be returned when searching for just "EMAIL". If you want to
+     * search for a property in a specific group, you can select on the entire
+     * string ("HOME.EMAIL"). If you want to search on a specific property that
+     * has not been assigned a group, specify ".EMAIL".
+     *
+     * Keys are retained from the 'children' array, which may be confusing in
+     * certain cases.
+     *
+     * @param string $name
+     * @return array
+     */
+    public function select($name) {
+
+        $group = null;
+        $name = strtoupper($name);
+        if (strpos($name,'.')!==false) {
+            list($group,$name) = explode('.', $name, 2);
+        }
+
+        $result = array();
+        foreach($this->children as $key=>$child) {
+
+            if (
+                strtoupper($child->name) === $name &&
+                (is_null($group) || ( $child instanceof Property && strtoupper($child->group) === $group))
+            ) {
+
+                $result[$key] = $child;
+
+            }
+        }
+
+        reset($result);
+        return $result;
+
+    }
+
+    /**
+     * This method only returns a list of sub-components. Properties are
+     * ignored.
+     *
+     * @return array
+     */
+    public function getComponents() {
+
+        $result = array();
+        foreach($this->children as $child) {
+            if ($child instanceof Component) {
+                $result[] = $child;
+            }
+        }
+
+        return $result;
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   - Node::REPAIR - If something is broken, and automatic repair may
+     *                    be attempted.
+     *
+     * An array is returned with warnings.
+     *
+     * Every item in the array has the following properties:
+     *    * level - (number between 1 and 3 with severity information)
+     *    * message - (human readable message)
+     *    * node - (reference to the offending node)
+     *
+     * @param int $options
+     * @return array
+     */
+    public function validate($options = 0) {
+
+        $result = array();
+        foreach($this->children as $child) {
+            $result = array_merge($result, $child->validate($options));
+        }
+        return $result;
+
+    }
+
+    /* Magic property accessors {{{ */
+
+    /**
+     * Using 'get' you will either get a property or component,
+     *
+     * If there were no child-elements found with the specified name,
+     * null is returned.
+     *
+     * @param string $name
+     * @return Property
+     */
+    public function __get($name) {
+
+        $matches = $this->select($name);
+        if (count($matches)===0) {
+            return null;
+        } else {
+            $firstMatch = current($matches);
+            /** @var $firstMatch Property */
+            $firstMatch->setIterator(new ElementList(array_values($matches)));
+            return $firstMatch;
+        }
+
+    }
+
+    /**
+     * This method checks if a sub-element with the specified name exists.
+     *
+     * @param string $name
+     * @return bool
+     */
+    public function __isset($name) {
+
+        $matches = $this->select($name);
+        return count($matches)>0;
+
+    }
+
+    /**
+     * Using the setter method you can add properties or subcomponents
+     *
+     * You can either pass a Component, Property
+     * object, or a string to automatically create a Property.
+     *
+     * If the item already exists, it will be removed. If you want to add
+     * a new item with the same name, always use the add() method.
+     *
+     * @param string $name
+     * @param mixed $value
+     * @return void
+     */
+    public function __set($name, $value) {
+
+        $matches = $this->select($name);
+        $overWrite = count($matches)?key($matches):null;
+
+        if ($value instanceof Component || $value instanceof Property) {
+            $value->parent = $this;
+            if (!is_null($overWrite)) {
+                $this->children[$overWrite] = $value;
+            } else {
+                $this->children[] = $value;
+            }
+        } elseif (is_scalar($value)) {
+            $property = Property::create($name,$value);
+            $property->parent = $this;
+            if (!is_null($overWrite)) {
+                $this->children[$overWrite] = $property;
+            } else {
+                $this->children[] = $property;
+            }
+        } else {
+            throw new \InvalidArgumentException('You must pass a \\Sabre\\VObject\\Component, \\Sabre\\VObject\\Property or scalar type');
+        }
+
+    }
+
+    /**
+     * Removes all properties and components within this component.
+     *
+     * @param string $name
+     * @return void
+     */
+    public function __unset($name) {
+
+        $matches = $this->select($name);
+        foreach($matches as $k=>$child) {
+
+            unset($this->children[$k]);
+            $child->parent = null;
+
+        }
+
+    }
+
+    /* }}} */
+
+    /**
+     * This method is automatically called when the object is cloned.
+     * Specifically, this will ensure all child elements are also cloned.
+     *
+     * @return void
+     */
+    public function __clone() {
+
+        foreach($this->children as $key=>$child) {
+            $this->children[$key] = clone $child;
+            $this->children[$key]->parent = $this;
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VAlarm.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VAlarm.php
new file mode 100644
index 000000000..2f86c44fd
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VAlarm.php
@@ -0,0 +1,108 @@
+<?php
+
+namespace Sabre\VObject\Component;
+use Sabre\VObject;
+
+/**
+ * VAlarm component
+ *
+ * This component contains some additional functionality specific for VALARMs.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VAlarm extends VObject\Component {
+
+    /**
+     * Returns a DateTime object when this alarm is going to trigger.
+     *
+     * This ignores repeated alarm, only the first trigger is returned.
+     *
+     * @return DateTime
+     */
+    public function getEffectiveTriggerTime() {
+
+        $trigger = $this->TRIGGER;
+        if(!isset($trigger['VALUE']) || strtoupper($trigger['VALUE']) === 'DURATION') {
+            $triggerDuration = VObject\DateTimeParser::parseDuration($this->TRIGGER);
+            $related = (isset($trigger['RELATED']) && strtoupper($trigger['RELATED']) == 'END') ? 'END' : 'START';
+
+            $parentComponent = $this->parent;
+            if ($related === 'START') {
+
+                if ($parentComponent->name === 'VTODO') {
+                    $propName = 'DUE';
+                } else {
+                    $propName = 'DTSTART';
+                }
+
+                $effectiveTrigger = clone $parentComponent->$propName->getDateTime();
+                $effectiveTrigger->add($triggerDuration);
+            } else {
+                if ($parentComponent->name === 'VTODO') {
+                    $endProp = 'DUE';
+                } elseif ($parentComponent->name === 'VEVENT') {
+                    $endProp = 'DTEND';
+                } else {
+                    throw new \LogicException('time-range filters on VALARM components are only supported when they are a child of VTODO or VEVENT');
+                }
+
+                if (isset($parentComponent->$endProp)) {
+                    $effectiveTrigger = clone $parentComponent->$endProp->getDateTime();
+                    $effectiveTrigger->add($triggerDuration);
+                } elseif (isset($parentComponent->DURATION)) {
+                    $effectiveTrigger = clone $parentComponent->DTSTART->getDateTime();
+                    $duration = VObject\DateTimeParser::parseDuration($parentComponent->DURATION);
+                    $effectiveTrigger->add($duration);
+                    $effectiveTrigger->add($triggerDuration);
+                } else {
+                    $effectiveTrigger = clone $parentComponent->DTSTART->getDateTime();
+                    $effectiveTrigger->add($triggerDuration);
+                }
+            }
+        } else {
+            $effectiveTrigger = $trigger->getDateTime();
+        }
+        return $effectiveTrigger;
+
+    }
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param \DateTime $start
+     * @param \DateTime $end
+     * @return bool
+     */
+    public function isInTimeRange(\DateTime $start, \DateTime $end) {
+
+        $effectiveTrigger = $this->getEffectiveTriggerTime();
+
+        if (isset($this->DURATION)) {
+            $duration = VObject\DateTimeParser::parseDuration($this->DURATION);
+            $repeat = (string)$this->repeat;
+            if (!$repeat) {
+                $repeat = 1;
+            }
+
+            $period = new \DatePeriod($effectiveTrigger, $duration, (int)$repeat);
+
+            foreach($period as $occurrence) {
+
+                if ($start <= $occurrence && $end > $occurrence) {
+                    return true;
+                }
+            }
+            return false;
+        } else {
+            return ($start <= $effectiveTrigger && $end > $effectiveTrigger);
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCalendar.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCalendar.php
new file mode 100644
index 000000000..9de67982e
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCalendar.php
@@ -0,0 +1,244 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * The VCalendar component
+ *
+ * This component adds functionality to a component, specific for a VCALENDAR.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VCalendar extends VObject\Document {
+
+    static $defaultName = 'VCALENDAR';
+
+    /**
+     * Returns a list of all 'base components'. For instance, if an Event has
+     * a recurrence rule, and one instance is overridden, the overridden event
+     * will have the same UID, but will be excluded from this list.
+     *
+     * VTIMEZONE components will always be excluded.
+     *
+     * @param string $componentName filter by component name
+     * @return array
+     */
+    public function getBaseComponents($componentName = null) {
+
+        $components = array();
+        foreach($this->children as $component) {
+
+            if (!$component instanceof VObject\Component)
+                continue;
+
+            if (isset($component->{'RECURRENCE-ID'}))
+                continue;
+
+            if ($componentName && $component->name !== strtoupper($componentName))
+                continue;
+
+            if ($component->name === 'VTIMEZONE')
+                continue;
+
+            $components[] = $component;
+
+        }
+
+        return $components;
+
+    }
+
+    /**
+     * If this calendar object, has events with recurrence rules, this method
+     * can be used to expand the event into multiple sub-events.
+     *
+     * Each event will be stripped from it's recurrence information, and only
+     * the instances of the event in the specified timerange will be left
+     * alone.
+     *
+     * In addition, this method will cause timezone information to be stripped,
+     * and normalized to UTC.
+     *
+     * This method will alter the VCalendar. This cannot be reversed.
+     *
+     * This functionality is specifically used by the CalDAV standard. It is
+     * possible for clients to request expand events, if they are rather simple
+     * clients and do not have the possibility to calculate recurrences.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     * @return void
+     */
+    public function expand(\DateTime $start, \DateTime $end) {
+
+        $newEvents = array();
+
+        foreach($this->select('VEVENT') as $key=>$vevent) {
+
+            if (isset($vevent->{'RECURRENCE-ID'})) {
+                unset($this->children[$key]);
+                continue;
+            }
+
+
+            if (!$vevent->rrule) {
+                unset($this->children[$key]);
+                if ($vevent->isInTimeRange($start, $end)) {
+                    $newEvents[] = $vevent;
+                }
+                continue;
+            }
+
+            $uid = (string)$vevent->uid;
+            if (!$uid) {
+                throw new \LogicException('Event did not have a UID!');
+            }
+
+            $it = new VObject\RecurrenceIterator($this, $vevent->uid);
+            $it->fastForward($start);
+
+            while($it->valid() && $it->getDTStart() < $end) {
+
+                if ($it->getDTEnd() > $start) {
+
+                    $newEvents[] = $it->getEventObject();
+
+                }
+                $it->next();
+
+            }
+            unset($this->children[$key]);
+
+        }
+
+        foreach($newEvents as $newEvent) {
+
+            foreach($newEvent->children as $child) {
+                if ($child instanceof VObject\Property\DateTime &&
+                    $child->getDateType() == VObject\Property\DateTime::LOCALTZ) {
+                        $child->setDateTime($child->getDateTime(),VObject\Property\DateTime::UTC);
+                    }
+            }
+
+            $this->add($newEvent);
+
+        }
+
+        // Removing all VTIMEZONE components
+        unset($this->VTIMEZONE);
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     * An array is returned with warnings.
+     *
+     * Every item in the array has the following properties:
+     *    * level - (number between 1 and 3 with severity information)
+     *    * message - (human readable message)
+     *    * node - (reference to the offending node)
+     *
+     * @return array
+     */
+    /*
+    public function validate() {
+
+        $warnings = array();
+
+        $version = $this->select('VERSION');
+        if (count($version)!==1) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'The VERSION property must appear in the VCALENDAR component exactly 1 time',
+                'node' => $this,
+            );
+        } else {
+            if ((string)$this->VERSION !== '2.0') {
+                $warnings[] = array(
+                    'level' => 1,
+                    'message' => 'Only iCalendar version 2.0 as defined in rfc5545 is supported.',
+                    'node' => $this,
+                );
+            }
+        }
+        $version = $this->select('PRODID');
+        if (count($version)!==1) {
+            $warnings[] = array(
+                'level' => 2,
+                'message' => 'The PRODID property must appear in the VCALENDAR component exactly 1 time',
+                'node' => $this,
+            );
+        }
+        if (count($this->CALSCALE) > 1) {
+            $warnings[] = array(
+                'level' => 2,
+                'message' => 'The CALSCALE property must not be specified more than once.',
+                'node' => $this,
+            );
+        }
+        if (count($this->METHOD) > 1) {
+            $warnings[] = array(
+                'level' => 2,
+                'message' => 'The METHOD property must not be specified more than once.',
+                'node' => $this,
+            );
+        }
+
+        $allowedComponents = array(
+            'VEVENT',
+            'VTODO',
+            'VJOURNAL',
+            'VFREEBUSY',
+            'VTIMEZONE',
+        );
+        $allowedProperties = array(
+            'PRODID',
+            'VERSION',
+            'CALSCALE',
+            'METHOD',
+        );
+        $componentsFound = 0;
+        foreach($this->children as $child) {
+            if($child instanceof Component) {
+                $componentsFound++;
+                if (!in_array($child->name, $allowedComponents)) {
+                    $warnings[] = array(
+                        'level' => 1,
+                        'message' => 'The ' . $child->name . " component is not allowed in the VCALENDAR component",
+                        'node' => $this,
+                    );
+                }
+            }
+            if ($child instanceof Property) {
+                if (!in_array($child->name, $allowedProperties)) {
+                    $warnings[] = array(
+                        'level' => 2,
+                        'message' => 'The ' . $child->name . " property is not allowed in the VCALENDAR component",
+                        'node' => $this,
+                    );
+                }
+            }
+        }
+
+        if ($componentsFound===0) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'An iCalendar object must have at least 1 component.',
+                'node' => $this,
+            );
+        }
+
+        return array_merge(
+            $warnings,
+            parent::validate()
+        );
+
+    }
+     */
+
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCard.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCard.php
new file mode 100644
index 000000000..0fc8b7020
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VCard.php
@@ -0,0 +1,107 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * The VCard component
+ *
+ * This component represents the BEGIN:VCARD and END:VCARD found in every
+ * vcard.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VCard extends VObject\Component {
+
+    static $defaultName = 'VCARD';
+
+    /**
+     * VCards with version 2.1, 3.0 and 4.0 are found.
+     *
+     * If the VCARD doesn't know its version, 4.0 is assumed.
+     */
+    const DEFAULT_VERSION = '4.0';
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   - Node::REPAIR - If something is broken, and automatic repair may
+     *                    be attempted.
+     *
+     * An array is returned with warnings.
+     *
+     * Every item in the array has the following properties:
+     *    * level - (number between 1 and 3 with severity information)
+     *    * message - (human readable message)
+     *    * node - (reference to the offending node)
+     *
+     * @param int $options
+     * @return array
+     */
+    public function validate($options = 0) {
+
+        $warnings = array();
+
+        $version = $this->select('VERSION');
+        if (count($version)!==1) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'The VERSION property must appear in the VCARD component exactly 1 time',
+                'node' => $this,
+            );
+            if ($options & self::REPAIR) {
+                $this->VERSION = self::DEFAULT_VERSION;
+            }
+        } else {
+            $version = (string)$this->VERSION;
+            if ($version!=='2.1' && $version!=='3.0' && $version!=='4.0') {
+                $warnings[] = array(
+                    'level' => 1,
+                    'message' => 'Only vcard version 4.0 (RFC6350), version 3.0 (RFC2426) or version 2.1 (icm-vcard-2.1) are supported.',
+                    'node' => $this,
+                );
+                if ($options & self::REPAIR) {
+                    $this->VERSION = '4.0';
+                }
+            }
+
+        }
+        $fn = $this->select('FN');
+        if (count($fn)!==1) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'The FN property must appear in the VCARD component exactly 1 time',
+                'node' => $this,
+            );
+            if (($options & self::REPAIR) && count($fn) === 0) {
+                // We're going to try to see if we can use the contents of the
+                // N property.
+                if (isset($this->N)) {
+                    $value = explode(';', (string)$this->N);
+                    if (isset($value[1]) && $value[1]) {
+                        $this->FN = $value[1] . ' ' . $value[0];
+                    } else {
+                        $this->FN = $value[0];
+                    }
+
+                // Otherwise, the ORG property may work
+                } elseif (isset($this->ORG)) {
+                    $this->FN = (string)$this->ORG;
+                }
+
+            }
+        }
+
+        return array_merge(
+            parent::validate($options),
+            $warnings
+        );
+
+    }
+
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VEvent.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VEvent.php
new file mode 100644
index 000000000..2375c5317
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VEvent.php
@@ -0,0 +1,70 @@
+<?php
+
+namespace Sabre\VObject\Component;
+use Sabre\VObject;
+
+/**
+ * VEvent component
+ *
+ * This component contains some additional functionality specific for VEVENT's.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VEvent extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param \DateTime $start
+     * @param \DateTime $end
+     * @return bool
+     */
+    public function isInTimeRange(\DateTime $start, \DateTime $end) {
+
+        if ($this->RRULE) {
+            $it = new VObject\RecurrenceIterator($this);
+            $it->fastForward($start);
+
+            // We fast-forwarded to a spot where the end-time of the
+            // recurrence instance exceeded the start of the requested
+            // time-range.
+            //
+            // If the starttime of the recurrence did not exceed the
+            // end of the time range as well, we have a match.
+            return ($it->getDTStart() < $end && $it->getDTEnd() > $start);
+
+        }
+
+        $effectiveStart = $this->DTSTART->getDateTime();
+        if (isset($this->DTEND)) {
+
+            // The DTEND property is considered non inclusive. So for a 3 day
+            // event in july, dtstart and dtend would have to be July 1st and
+            // July 4th respectively.
+            //
+            // See:
+            // http://tools.ietf.org/html/rfc5545#page-54
+            $effectiveEnd = $this->DTEND->getDateTime();
+
+        } elseif (isset($this->DURATION)) {
+            $effectiveEnd = clone $effectiveStart;
+            $effectiveEnd->add( VObject\DateTimeParser::parseDuration($this->DURATION) );
+        } elseif ($this->DTSTART->getDateType() == VObject\Property\DateTime::DATE) {
+            $effectiveEnd = clone $effectiveStart;
+            $effectiveEnd->modify('+1 day');
+        } else {
+            $effectiveEnd = clone $effectiveStart;
+        }
+        return (
+            ($start <= $effectiveEnd) && ($end > $effectiveStart)
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VFreeBusy.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VFreeBusy.php
new file mode 100644
index 000000000..7afe9fdb3
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VFreeBusy.php
@@ -0,0 +1,68 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * The VFreeBusy component
+ *
+ * This component adds functionality to a component, specific for VFREEBUSY
+ * components.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VFreeBusy extends VObject\Component {
+
+    /**
+     * Checks based on the contained FREEBUSY information, if a timeslot is
+     * available.
+     *
+     * @param DateTime $start
+     * @param Datetime $end
+     * @return bool
+     */
+    public function isFree(\DateTime $start, \Datetime $end) {
+
+        foreach($this->select('FREEBUSY') as $freebusy) {
+
+            // We are only interested in FBTYPE=BUSY (the default),
+            // FBTYPE=BUSY-TENTATIVE or FBTYPE=BUSY-UNAVAILABLE.
+            if (isset($freebusy['FBTYPE']) && strtoupper(substr((string)$freebusy['FBTYPE'],0,4))!=='BUSY') {
+                continue;
+            }
+
+            // The freebusy component can hold more than 1 value, separated by
+            // commas.
+            $periods = explode(',', (string)$freebusy);
+
+            foreach($periods as $period) {
+                // Every period is formatted as [start]/[end]. The start is an
+                // absolute UTC time, the end may be an absolute UTC time, or
+                // duration (relative) value.
+                list($busyStart, $busyEnd) = explode('/', $period);
+
+                $busyStart = VObject\DateTimeParser::parse($busyStart);
+                $busyEnd = VObject\DateTimeParser::parse($busyEnd);
+                if ($busyEnd instanceof \DateInterval) {
+                    $tmp = clone $busyStart;
+                    $tmp->add($busyEnd);
+                    $busyEnd = $tmp;
+                }
+
+                if($start < $busyEnd && $end > $busyStart) {
+                    return false;
+                }
+
+            }
+
+        }
+
+        return true;
+
+    }
+
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VJournal.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VJournal.php
new file mode 100644
index 000000000..232887879
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VJournal.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * VJournal component
+ *
+ * This component contains some additional functionality specific for VJOURNALs.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VJournal extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     * @return bool
+     */
+    public function isInTimeRange(\DateTime $start, \DateTime $end) {
+
+        $dtstart = isset($this->DTSTART)?$this->DTSTART->getDateTime():null;
+        if ($dtstart) {
+            $effectiveEnd = clone $dtstart;
+            if ($this->DTSTART->getDateType() == VObject\Property\DateTime::DATE) {
+                $effectiveEnd->modify('+1 day');
+            }
+
+            return ($start <= $effectiveEnd && $end > $dtstart);
+
+        }
+        return false;
+
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Component/VTodo.php b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VTodo.php
new file mode 100644
index 000000000..b1579cf74
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Component/VTodo.php
@@ -0,0 +1,68 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * VTodo component
+ *
+ * This component contains some additional functionality specific for VTODOs.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VTodo extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     * @return bool
+     */
+    public function isInTimeRange(\DateTime $start, \DateTime $end) {
+
+        $dtstart = isset($this->DTSTART)?$this->DTSTART->getDateTime():null;
+        $duration = isset($this->DURATION)?VObject\DateTimeParser::parseDuration($this->DURATION):null;
+        $due = isset($this->DUE)?$this->DUE->getDateTime():null;
+        $completed = isset($this->COMPLETED)?$this->COMPLETED->getDateTime():null;
+        $created = isset($this->CREATED)?$this->CREATED->getDateTime():null;
+
+        if ($dtstart) {
+            if ($duration) {
+                $effectiveEnd = clone $dtstart;
+                $effectiveEnd->add($duration);
+                return $start <= $effectiveEnd && $end > $dtstart;
+            } elseif ($due) {
+                return
+                    ($start < $due || $start <= $dtstart) &&
+                    ($end > $dtstart || $end >= $due);
+            } else {
+                return $start <= $dtstart && $end > $dtstart;
+            }
+        }
+        if ($due) {
+            return ($start < $due && $end >= $due);
+        }
+        if ($completed && $created) {
+            return
+                ($start <= $created || $start <= $completed) &&
+                ($end >= $created || $end >= $completed);
+        }
+        if ($completed) {
+            return ($start <= $completed && $end >= $completed);
+        }
+        if ($created) {
+            return ($end > $created);
+        }
+        return true;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/DateTimeParser.php b/vendor/sabre/vobject/lib/Sabre/VObject/DateTimeParser.php
new file mode 100644
index 000000000..03600506d
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/DateTimeParser.php
@@ -0,0 +1,181 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * DateTimeParser
+ *
+ * This class is responsible for parsing the several different date and time
+ * formats iCalendar and vCards have.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class DateTimeParser {
+
+    /**
+     * Parses an iCalendar (rfc5545) formatted datetime and returns a DateTime object
+     *
+     * Specifying a reference timezone is optional. It will only be used
+     * if the non-UTC format is used. The argument is used as a reference, the
+     * returned DateTime object will still be in the UTC timezone.
+     *
+     * @param string $dt
+     * @param DateTimeZone $tz
+     * @return DateTime
+     */
+    static public function parseDateTime($dt,\DateTimeZone $tz = null) {
+
+        // Format is YYYYMMDD + "T" + hhmmss
+        $result = preg_match('/^([1-4][0-9]{3})([0-1][0-9])([0-3][0-9])T([0-2][0-9])([0-5][0-9])([0-5][0-9])([Z]?)$/',$dt,$matches);
+
+        if (!$result) {
+            throw new \LogicException('The supplied iCalendar datetime value is incorrect: ' . $dt);
+        }
+
+        if ($matches[7]==='Z' || is_null($tz)) {
+            $tz = new \DateTimeZone('UTC');
+        }
+        $date = new \DateTime($matches[1] . '-' . $matches[2] . '-' . $matches[3] . ' ' . $matches[4] . ':' . $matches[5] .':' . $matches[6], $tz);
+
+        // Still resetting the timezone, to normalize everything to UTC
+        $date->setTimeZone(new \DateTimeZone('UTC'));
+        return $date;
+
+    }
+
+    /**
+     * Parses an iCalendar (rfc5545) formatted date and returns a DateTime object
+     *
+     * @param string $date
+     * @return DateTime
+     */
+    static public function parseDate($date) {
+
+        // Format is YYYYMMDD
+        $result = preg_match('/^([1-4][0-9]{3})([0-1][0-9])([0-3][0-9])$/',$date,$matches);
+
+        if (!$result) {
+            throw new \LogicException('The supplied iCalendar date value is incorrect: ' . $date);
+        }
+
+        $date = new \DateTime($matches[1] . '-' . $matches[2] . '-' . $matches[3], new \DateTimeZone('UTC'));
+        return $date;
+
+    }
+
+    /**
+     * Parses an iCalendar (RFC5545) formatted duration value.
+     *
+     * This method will either return a DateTimeInterval object, or a string
+     * suitable for strtotime or DateTime::modify.
+     *
+     * @param string $duration
+     * @param bool $asString
+     * @return DateInterval|string
+     */
+    static public function parseDuration($duration, $asString = false) {
+
+        $result = preg_match('/^(?P<plusminus>\+|-)?P((?P<week>\d+)W)?((?P<day>\d+)D)?(T((?P<hour>\d+)H)?((?P<minute>\d+)M)?((?P<second>\d+)S)?)?$/', $duration, $matches);
+        if (!$result) {
+            throw new \LogicException('The supplied iCalendar duration value is incorrect: ' . $duration);
+        }
+
+        if (!$asString) {
+            $invert = false;
+            if ($matches['plusminus']==='-') {
+                $invert = true;
+            }
+
+
+            $parts = array(
+                'week',
+                'day',
+                'hour',
+                'minute',
+                'second',
+            );
+            foreach($parts as $part) {
+                $matches[$part] = isset($matches[$part])&&$matches[$part]?(int)$matches[$part]:0;
+            }
+
+
+            // We need to re-construct the $duration string, because weeks and
+            // days are not supported by DateInterval in the same string.
+            $duration = 'P';
+            $days = $matches['day'];
+            if ($matches['week']) {
+                $days+=$matches['week']*7;
+            }
+            if ($days)
+                $duration.=$days . 'D';
+
+            if ($matches['minute'] || $matches['second'] || $matches['hour']) {
+                $duration.='T';
+
+                if ($matches['hour'])
+                    $duration.=$matches['hour'].'H';
+
+                if ($matches['minute'])
+                    $duration.=$matches['minute'].'M';
+
+                if ($matches['second'])
+                    $duration.=$matches['second'].'S';
+
+            }
+
+            if ($duration==='P') {
+                $duration = 'PT0S';
+            }
+            $iv = new \DateInterval($duration);
+            if ($invert) $iv->invert = true;
+
+            return $iv;
+
+        }
+
+
+
+        $parts = array(
+            'week',
+            'day',
+            'hour',
+            'minute',
+            'second',
+        );
+
+        $newDur = '';
+        foreach($parts as $part) {
+            if (isset($matches[$part]) && $matches[$part]) {
+                $newDur.=' '.$matches[$part] . ' ' . $part . 's';
+            }
+        }
+
+        $newDur = ($matches['plusminus']==='-'?'-':'+') . trim($newDur);
+        if ($newDur === '+') { $newDur = '+0 seconds'; };
+        return $newDur;
+
+    }
+
+    /**
+     * Parses either a Date or DateTime, or Duration value.
+     *
+     * @param string $date
+     * @param DateTimeZone|string $referenceTZ
+     * @return DateTime|DateInterval
+     */
+    static public function parse($date, $referenceTZ = null) {
+
+        if ($date[0]==='P' || ($date[0]==='-' && $date[1]==='P')) {
+            return self::parseDuration($date);
+        } elseif (strlen($date)===8) {
+            return self::parseDate($date);
+        } else {
+            return self::parseDateTime($date, $referenceTZ);
+        }
+
+    }
+
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Document.php b/vendor/sabre/vobject/lib/Sabre/VObject/Document.php
new file mode 100644
index 000000000..50a662ee9
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Document.php
@@ -0,0 +1,109 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * Document
+ *
+ * A document is just like a component, except that it's also the top level
+ * element.
+ *
+ * Both a VCALENDAR and a VCARD are considered documents.
+ *
+ * This class also provides a registry for document types.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH. All rights reserved.
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+abstract class Document extends Component {
+
+    /**
+     * The default name for this component.
+     *
+     * This should be 'VCALENDAR' or 'VCARD'.
+     *
+     * @var string
+     */
+    static $defaultName;
+
+    /**
+     * Creates a new document.
+     *
+     * We're changing the default behavior slightly here. First, we don't want
+     * to have to specify a name (we already know it), and we want to allow
+     * children to be specified in the first argument.
+     *
+     * But, the default behavior also works.
+     *
+     * So the two sigs:
+     *
+     * new Document(array $children = array());
+     * new Document(string $name, array $children = array())
+     *
+     * @return void
+     */
+    public function __construct() {
+
+        $args = func_get_args();
+        if (count($args)===0 || is_array($args[0])) {
+            array_unshift($args, static::$defaultName);
+            call_user_func_array(array('parent', '__construct'), $args);
+        } else {
+            call_user_func_array(array('parent', '__construct'), $args);
+        }
+
+    }
+
+    /**
+     * Creates a new component
+     *
+     * This method automatically searches for the correct component class, based
+     * on its name.
+     *
+     * You can specify the children either in key=>value syntax, in which case
+     * properties will automatically be created, or you can just pass a list of
+     * Component and Property object.
+     *
+     * @param string $name
+     * @param array $children
+     * @return Component
+     */
+    public function createComponent($name, array $children = array()) {
+
+        $component = Component::create($name);
+        foreach($children as $k=>$v) {
+
+            if ($v instanceof Node) {
+                $component->add($v);
+            } else {
+                $component->add($k, $v);
+            }
+
+        }
+        return $component;
+
+    }
+
+    /**
+     * Factory method for creating new properties
+     *
+     * This method automatically searches for the correct property class, based
+     * on its name.
+     *
+     * You can specify the parameters either in key=>value syntax, in which case
+     * parameters will automatically be created, or you can just pass a list of
+     * Parameter objects.
+     *
+     * @param string $name
+     * @param mixed $value
+     * @param array $parameters
+     * @return Property
+     */
+    public function createProperty($name, $value = null, array $parameters = array()) {
+
+        return Property::create($name, $value, $parameters);
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/ElementList.php b/vendor/sabre/vobject/lib/Sabre/VObject/ElementList.php
new file mode 100644
index 000000000..1c203708e
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/ElementList.php
@@ -0,0 +1,172 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VObject ElementList
+ *
+ * This class represents a list of elements. Lists are the result of queries,
+ * such as doing $vcalendar->vevent where there's multiple VEVENT objects.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class ElementList implements \Iterator, \Countable, \ArrayAccess {
+
+    /**
+     * Inner elements
+     *
+     * @var array
+     */
+    protected $elements = array();
+
+    /**
+     * Creates the element list.
+     *
+     * @param array $elements
+     */
+    public function __construct(array $elements) {
+
+        $this->elements = $elements;
+
+    }
+
+    /* {{{ Iterator interface */
+
+    /**
+     * Current position
+     *
+     * @var int
+     */
+    private $key = 0;
+
+    /**
+     * Returns current item in iteration
+     *
+     * @return Element
+     */
+    public function current() {
+
+        return $this->elements[$this->key];
+
+    }
+
+    /**
+     * To the next item in the iterator
+     *
+     * @return void
+     */
+    public function next() {
+
+        $this->key++;
+
+    }
+
+    /**
+     * Returns the current iterator key
+     *
+     * @return int
+     */
+    public function key() {
+
+        return $this->key;
+
+    }
+
+    /**
+     * Returns true if the current position in the iterator is a valid one
+     *
+     * @return bool
+     */
+    public function valid() {
+
+        return isset($this->elements[$this->key]);
+
+    }
+
+    /**
+     * Rewinds the iterator
+     *
+     * @return void
+     */
+    public function rewind() {
+
+        $this->key = 0;
+
+    }
+
+    /* }}} */
+
+    /* {{{ Countable interface */
+
+    /**
+     * Returns the number of elements
+     *
+     * @return int
+     */
+    public function count() {
+
+        return count($this->elements);
+
+    }
+
+    /* }}} */
+
+    /* {{{ ArrayAccess Interface */
+
+
+    /**
+     * Checks if an item exists through ArrayAccess.
+     *
+     * @param int $offset
+     * @return bool
+     */
+    public function offsetExists($offset) {
+
+        return isset($this->elements[$offset]);
+
+    }
+
+    /**
+     * Gets an item through ArrayAccess.
+     *
+     * @param int $offset
+     * @return mixed
+     */
+    public function offsetGet($offset) {
+
+        return $this->elements[$offset];
+
+    }
+
+    /**
+     * Sets an item through ArrayAccess.
+     *
+     * @param int $offset
+     * @param mixed $value
+     * @return void
+     */
+    public function offsetSet($offset,$value) {
+
+        throw new \LogicException('You can not add new objects to an ElementList');
+
+    }
+
+    /**
+     * Sets an item through ArrayAccess.
+     *
+     * This method just forwards the request to the inner iterator
+     *
+     * @param int $offset
+     * @return void
+     */
+    public function offsetUnset($offset) {
+
+        throw new \LogicException('You can not remove objects from an ElementList');
+
+    }
+
+    /* }}} */
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/FreeBusyGenerator.php b/vendor/sabre/vobject/lib/Sabre/VObject/FreeBusyGenerator.php
new file mode 100644
index 000000000..96d0be5ac
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/FreeBusyGenerator.php
@@ -0,0 +1,322 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * This class helps with generating FREEBUSY reports based on existing sets of
+ * objects.
+ *
+ * It only looks at VEVENT and VFREEBUSY objects from the sourcedata, and
+ * generates a single VFREEBUSY object.
+ *
+ * VFREEBUSY components are described in RFC5545, The rules for what should
+ * go in a single freebusy report is taken from RFC4791, section 7.10.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class FreeBusyGenerator {
+
+    /**
+     * Input objects
+     *
+     * @var array
+     */
+    protected $objects;
+
+    /**
+     * Start of range
+     *
+     * @var DateTime|null
+     */
+    protected $start;
+
+    /**
+     * End of range
+     *
+     * @var DateTime|null
+     */
+    protected $end;
+
+    /**
+     * VCALENDAR object
+     *
+     * @var Component
+     */
+    protected $baseObject;
+
+    /**
+     * Creates the generator.
+     *
+     * Check the setTimeRange and setObjects methods for details about the
+     * arguments.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     * @param mixed $objects
+     * @return void
+     */
+    public function __construct(\DateTime $start = null, \DateTime $end = null, $objects = null) {
+
+        if ($start && $end) {
+            $this->setTimeRange($start, $end);
+        }
+
+        if ($objects) {
+            $this->setObjects($objects);
+        }
+
+    }
+
+    /**
+     * Sets the VCALENDAR object.
+     *
+     * If this is set, it will not be generated for you. You are responsible
+     * for setting things like the METHOD, CALSCALE, VERSION, etc..
+     *
+     * The VFREEBUSY object will be automatically added though.
+     *
+     * @param Component $vcalendar
+     * @return void
+     */
+    public function setBaseObject(Component $vcalendar) {
+
+        $this->baseObject = $vcalendar;
+
+    }
+
+    /**
+     * Sets the input objects
+     *
+     * You must either specify a valendar object as a strong, or as the parse
+     * Component.
+     * It's also possible to specify multiple objects as an array.
+     *
+     * @param mixed $objects
+     * @return void
+     */
+    public function setObjects($objects) {
+
+        if (!is_array($objects)) {
+            $objects = array($objects);
+        }
+
+        $this->objects = array();
+        foreach($objects as $object) {
+
+            if (is_string($object)) {
+                $this->objects[] = Reader::read($object);
+            } elseif ($object instanceof Component) {
+                $this->objects[] = $object;
+            } else {
+                throw new \InvalidArgumentException('You can only pass strings or \\Sabre\\VObject\\Component arguments to setObjects');
+            }
+
+        }
+
+    }
+
+    /**
+     * Sets the time range
+     *
+     * Any freebusy object falling outside of this time range will be ignored.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     * @return void
+     */
+    public function setTimeRange(\DateTime $start = null, \DateTime $end = null) {
+
+        $this->start = $start;
+        $this->end = $end;
+
+    }
+
+    /**
+     * Parses the input data and returns a correct VFREEBUSY object, wrapped in
+     * a VCALENDAR.
+     *
+     * @return Component
+     */
+    public function getResult() {
+
+        $busyTimes = array();
+
+        foreach($this->objects as $object) {
+
+            foreach($object->getBaseComponents() as $component) {
+
+                switch($component->name) {
+
+                    case 'VEVENT' :
+
+                        $FBTYPE = 'BUSY';
+                        if (isset($component->TRANSP) && (strtoupper($component->TRANSP) === 'TRANSPARENT')) {
+                            break;
+                        }
+                        if (isset($component->STATUS)) {
+                            $status = strtoupper($component->STATUS);
+                            if ($status==='CANCELLED') {
+                                break;
+                            }
+                            if ($status==='TENTATIVE') {
+                                $FBTYPE = 'BUSY-TENTATIVE';
+                            }
+                        }
+
+                        $times = array();
+
+                        if ($component->RRULE) {
+
+                            $iterator = new RecurrenceIterator($object, (string)$component->uid);
+                            if ($this->start) {
+                                $iterator->fastForward($this->start);
+                            }
+
+                            $maxRecurrences = 200;
+
+                            while($iterator->valid() && --$maxRecurrences) {
+
+                                $startTime = $iterator->getDTStart();
+                                if ($this->end && $startTime > $this->end) {
+                                    break;
+                                }
+                                $times[] = array(
+                                    $iterator->getDTStart(),
+                                    $iterator->getDTEnd(),
+                                );
+
+                                $iterator->next();
+
+                            }
+
+                        } else {
+
+                            $startTime = $component->DTSTART->getDateTime();
+                            if ($this->end && $startTime > $this->end) {
+                                break;
+                            }
+                            $endTime = null;
+                            if (isset($component->DTEND)) {
+                                $endTime = $component->DTEND->getDateTime();
+                            } elseif (isset($component->DURATION)) {
+                                $duration = DateTimeParser::parseDuration((string)$component->DURATION);
+                                $endTime = clone $startTime;
+                                $endTime->add($duration);
+                            } elseif ($component->DTSTART->getDateType() === Property\DateTime::DATE) {
+                                $endTime = clone $startTime;
+                                $endTime->modify('+1 day');
+                            } else {
+                                // The event had no duration (0 seconds)
+                                break;
+                            }
+
+                            $times[] = array($startTime, $endTime);
+
+                        }
+
+                        foreach($times as $time) {
+
+                            if ($this->end && $time[0] > $this->end) break;
+                            if ($this->start && $time[1] < $this->start) break;
+
+                            $busyTimes[] = array(
+                                $time[0],
+                                $time[1],
+                                $FBTYPE,
+                            );
+                        }
+                        break;
+
+                    case 'VFREEBUSY' :
+                        foreach($component->FREEBUSY as $freebusy) {
+
+                            $fbType = isset($freebusy['FBTYPE'])?strtoupper($freebusy['FBTYPE']):'BUSY';
+
+                            // Skipping intervals marked as 'free'
+                            if ($fbType==='FREE')
+                                continue;
+
+                            $values = explode(',', $freebusy);
+                            foreach($values as $value) {
+                                list($startTime, $endTime) = explode('/', $value);
+                                $startTime = DateTimeParser::parseDateTime($startTime);
+
+                                if (substr($endTime,0,1)==='P' || substr($endTime,0,2)==='-P') {
+                                    $duration = DateTimeParser::parseDuration($endTime);
+                                    $endTime = clone $startTime;
+                                    $endTime->add($duration);
+                                } else {
+                                    $endTime = DateTimeParser::parseDateTime($endTime);
+                                }
+
+                                if($this->start && $this->start > $endTime) continue;
+                                if($this->end && $this->end < $startTime) continue;
+                                $busyTimes[] = array(
+                                    $startTime,
+                                    $endTime,
+                                    $fbType
+                                );
+
+                            }
+
+
+                        }
+                        break;
+
+
+
+                }
+
+
+            }
+
+        }
+
+        if ($this->baseObject) {
+            $calendar = $this->baseObject;
+        } else {
+            $calendar = Component::create('VCALENDAR');
+            $calendar->version = '2.0';
+            $calendar->prodid = '-//Sabre//Sabre VObject ' . Version::VERSION . '//EN';
+            $calendar->calscale = 'GREGORIAN';
+        }
+
+        $vfreebusy = Component::create('VFREEBUSY');
+        $calendar->add($vfreebusy);
+
+        if ($this->start) {
+            $dtstart = Property::create('DTSTART');
+            $dtstart->setDateTime($this->start,Property\DateTime::UTC);
+            $vfreebusy->add($dtstart);
+        }
+        if ($this->end) {
+            $dtend = Property::create('DTEND');
+            $dtend->setDateTime($this->end,Property\DateTime::UTC);
+            $vfreebusy->add($dtend);
+        }
+        $dtstamp = Property::create('DTSTAMP');
+        $dtstamp->setDateTime(new \DateTime('now'), Property\DateTime::UTC);
+        $vfreebusy->add($dtstamp);
+
+        foreach($busyTimes as $busyTime) {
+
+            $busyTime[0]->setTimeZone(new \DateTimeZone('UTC'));
+            $busyTime[1]->setTimeZone(new \DateTimeZone('UTC'));
+
+            $prop = Property::create(
+                'FREEBUSY',
+                $busyTime[0]->format('Ymd\\THis\\Z') . '/' . $busyTime[1]->format('Ymd\\THis\\Z')
+            );
+            $prop['FBTYPE'] = $busyTime[2];
+            $vfreebusy->add($prop);
+
+        }
+
+        return $calendar;
+
+    }
+
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Node.php b/vendor/sabre/vobject/lib/Sabre/VObject/Node.php
new file mode 100644
index 000000000..bee68ec2a
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Node.php
@@ -0,0 +1,187 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * Base class for all nodes
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+abstract class Node implements \IteratorAggregate, \ArrayAccess, \Countable {
+
+    /**
+     * The following constants are used by the validate() method.
+     */
+    const REPAIR = 1;
+
+    /**
+     * Turns the object back into a serialized blob.
+     *
+     * @return string
+     */
+    abstract function serialize();
+
+    /**
+     * Iterator override
+     *
+     * @var ElementList
+     */
+    protected $iterator = null;
+
+    /**
+     * A link to the parent node
+     *
+     * @var Node
+     */
+    public $parent = null;
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   - Node::REPAIR - If something is broken, and automatic repair may
+     *                    be attempted.
+     *
+     * An array is returned with warnings.
+     *
+     * Every item in the array has the following properties:
+     *    * level - (number between 1 and 3 with severity information)
+     *    * message - (human readable message)
+     *    * node - (reference to the offending node)
+     *
+     * @param int $options
+     * @return array
+     */
+    public function validate($options = 0) {
+
+        return array();
+
+    }
+
+    /* {{{ IteratorAggregator interface */
+
+    /**
+     * Returns the iterator for this object
+     *
+     * @return ElementList
+     */
+    public function getIterator() {
+
+        if (!is_null($this->iterator))
+            return $this->iterator;
+
+        return new ElementList(array($this));
+
+    }
+
+    /**
+     * Sets the overridden iterator
+     *
+     * Note that this is not actually part of the iterator interface
+     *
+     * @param ElementList $iterator
+     * @return void
+     */
+    public function setIterator(ElementList $iterator) {
+
+        $this->iterator = $iterator;
+
+    }
+
+    /* }}} */
+
+    /* {{{ Countable interface */
+
+    /**
+     * Returns the number of elements
+     *
+     * @return int
+     */
+    public function count() {
+
+        $it = $this->getIterator();
+        return $it->count();
+
+    }
+
+    /* }}} */
+
+    /* {{{ ArrayAccess Interface */
+
+
+    /**
+     * Checks if an item exists through ArrayAccess.
+     *
+     * This method just forwards the request to the inner iterator
+     *
+     * @param int $offset
+     * @return bool
+     */
+    public function offsetExists($offset) {
+
+        $iterator = $this->getIterator();
+        return $iterator->offsetExists($offset);
+
+    }
+
+    /**
+     * Gets an item through ArrayAccess.
+     *
+     * This method just forwards the request to the inner iterator
+     *
+     * @param int $offset
+     * @return mixed
+     */
+    public function offsetGet($offset) {
+
+        $iterator = $this->getIterator();
+        return $iterator->offsetGet($offset);
+
+    }
+
+    /**
+     * Sets an item through ArrayAccess.
+     *
+     * This method just forwards the request to the inner iterator
+     *
+     * @param int $offset
+     * @param mixed $value
+     * @return void
+     */
+    public function offsetSet($offset,$value) {
+
+        $iterator = $this->getIterator();
+        $iterator->offsetSet($offset,$value);
+
+    // @codeCoverageIgnoreStart
+    //
+    // This method always throws an exception, so we ignore the closing
+    // brace
+    }
+    // @codeCoverageIgnoreEnd
+
+    /**
+     * Sets an item through ArrayAccess.
+     *
+     * This method just forwards the request to the inner iterator
+     *
+     * @param int $offset
+     * @return void
+     */
+    public function offsetUnset($offset) {
+
+        $iterator = $this->getIterator();
+        $iterator->offsetUnset($offset);
+
+    // @codeCoverageIgnoreStart
+    //
+    // This method always throws an exception, so we ignore the closing
+    // brace
+    }
+    // @codeCoverageIgnoreEnd
+
+    /* }}} */
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Parameter.php b/vendor/sabre/vobject/lib/Sabre/VObject/Parameter.php
new file mode 100644
index 000000000..72bf03b47
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Parameter.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VObject Parameter
+ *
+ * This class represents a parameter. A parameter is always tied to a property.
+ * In the case of:
+ *   DTSTART;VALUE=DATE:20101108
+ * VALUE=DATE would be the parameter name and value.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Parameter extends Node {
+
+    /**
+     * Parameter name
+     *
+     * @var string
+     */
+    public $name;
+
+    /**
+     * Parameter value
+     *
+     * @var string
+     */
+    public $value;
+
+    /**
+     * Sets up the object
+     *
+     * @param string $name
+     * @param string $value
+     */
+    public function __construct($name, $value = null) {
+
+        if (!is_scalar($value) && !is_null($value)) {
+            throw new \InvalidArgumentException('The value argument must be a scalar value or null');
+        }
+
+        $this->name = strtoupper($name);
+        $this->value = $value;
+
+    }
+
+    /**
+     * Returns the parameter's internal value.
+     *
+     * @return string
+     */
+    public function getValue() {
+
+        return $this->value;
+
+    }
+
+
+    /**
+     * Turns the object back into a serialized blob.
+     *
+     * @return string
+     */
+    public function serialize() {
+
+        if (is_null($this->value)) {
+            return $this->name;
+        }
+        $src = array(
+            '\\',
+            "\n",
+            ';',
+            ',',
+        );
+        $out = array(
+            '\\\\',
+            '\n',
+            '\;',
+            '\,',
+        );
+
+        $value = str_replace($src, $out, $this->value);
+        if (strpos($value,":")!==false) {
+            $value = '"' . $value . '"';
+        }
+        return $this->name . '=' . $value;
+
+    }
+
+    /**
+     * Called when this object is being cast to a string
+     *
+     * @return string
+     */
+    public function __toString() {
+
+        return $this->value;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/ParseException.php b/vendor/sabre/vobject/lib/Sabre/VObject/ParseException.php
new file mode 100644
index 000000000..66b49c606
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/ParseException.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * Exception thrown by Reader if an invalid object was attempted to be parsed.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class ParseException extends \Exception { }
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Property.php b/vendor/sabre/vobject/lib/Sabre/VObject/Property.php
new file mode 100644
index 000000000..63ae64574
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Property.php
@@ -0,0 +1,444 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VObject Property
+ *
+ * A property in VObject is usually in the form PARAMNAME:paramValue.
+ * An example is : SUMMARY:Weekly meeting
+ *
+ * Properties can also have parameters:
+ * SUMMARY;LANG=en:Weekly meeting.
+ *
+ * Parameters can be accessed using the ArrayAccess interface.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Property extends Node {
+
+    /**
+     * Propertyname
+     *
+     * @var string
+     */
+    public $name;
+
+    /**
+     * Group name
+     *
+     * This may be something like 'HOME' for vcards.
+     *
+     * @var string
+     */
+    public $group;
+
+    /**
+     * Property parameters
+     *
+     * @var array
+     */
+    public $parameters = array();
+
+    /**
+     * Property value
+     *
+     * @var string
+     */
+    public $value;
+
+    /**
+     * If properties are added to this map, they will be automatically mapped
+     * to their respective classes, if parsed by the reader or constructed with
+     * the 'create' method.
+     *
+     * @var array
+     */
+    static public $classMap = array(
+        'COMPLETED'     => 'Sabre\\VObject\\Property\\DateTime',
+        'CREATED'       => 'Sabre\\VObject\\Property\\DateTime',
+        'DTEND'         => 'Sabre\\VObject\\Property\\DateTime',
+        'DTSTAMP'       => 'Sabre\\VObject\\Property\\DateTime',
+        'DTSTART'       => 'Sabre\\VObject\\Property\\DateTime',
+        'DUE'           => 'Sabre\\VObject\\Property\\DateTime',
+        'EXDATE'        => 'Sabre\\VObject\\Property\\MultiDateTime',
+        'LAST-MODIFIED' => 'Sabre\\VObject\\Property\\DateTime',
+        'RECURRENCE-ID' => 'Sabre\\VObject\\Property\\DateTime',
+        'TRIGGER'       => 'Sabre\\VObject\\Property\\DateTime',
+        'N'             => 'Sabre\\VObject\\Property\\Compound',
+        'ORG'           => 'Sabre\\VObject\\Property\\Compound',
+        'ADR'           => 'Sabre\\VObject\\Property\\Compound',
+        'CATEGORIES'    => 'Sabre\\VObject\\Property\\Compound',
+    );
+
+    /**
+     * Creates the new property by name, but in addition will also see if
+     * there's a class mapped to the property name.
+     *
+     * Parameters can be specified with the optional third argument. Parameters
+     * must be a key->value map of the parameter name, and value. If the value
+     * is specified as an array, it is assumed that multiple parameters with
+     * the same name should be added.
+     *
+     * @param string $name
+     * @param string $value
+     * @param array $parameters
+     * @return Property
+     */
+    static public function create($name, $value = null, array $parameters = array()) {
+
+        $name = strtoupper($name);
+        $shortName = $name;
+        $group = null;
+        if (strpos($shortName,'.')!==false) {
+            list($group, $shortName) = explode('.', $shortName);
+        }
+
+        if (isset(self::$classMap[$shortName])) {
+            return new self::$classMap[$shortName]($name, $value, $parameters);
+        } else {
+            return new self($name, $value, $parameters);
+        }
+
+    }
+
+    /**
+     * Creates a new property object
+     *
+     * Parameters can be specified with the optional third argument. Parameters
+     * must be a key->value map of the parameter name, and value. If the value
+     * is specified as an array, it is assumed that multiple parameters with
+     * the same name should be added.
+     *
+     * @param string $name
+     * @param string $value
+     * @param array $parameters
+     */
+    public function __construct($name, $value = null, array $parameters = array()) {
+
+        if (!is_scalar($value) && !is_null($value)) {
+            throw new \InvalidArgumentException('The value argument must be scalar or null');
+        }
+
+        $name = strtoupper($name);
+        $group = null;
+        if (strpos($name,'.')!==false) {
+            list($group, $name) = explode('.', $name);
+        }
+        $this->name = $name;
+        $this->group = $group;
+        $this->setValue($value);
+
+        foreach($parameters as $paramName => $paramValues) {
+
+            if (!is_array($paramValues)) {
+                $paramValues = array($paramValues);
+            }
+
+            foreach($paramValues as $paramValue) {
+                $this->add($paramName, $paramValue);
+            }
+
+        }
+
+    }
+
+    /**
+     * Updates the internal value
+     *
+     * @param string $value
+     * @return void
+     */
+    public function setValue($value) {
+
+        $this->value = $value;
+
+    }
+
+    /**
+     * Returns the internal value
+     *
+     * @param string $value
+     * @return string
+     */
+    public function getValue() {
+
+        return $this->value;
+
+    }
+
+    /**
+     * Turns the object back into a serialized blob.
+     *
+     * @return string
+     */
+    public function serialize() {
+
+        $str = $this->name;
+        if ($this->group) $str = $this->group . '.' . $this->name;
+
+        foreach($this->parameters as $param) {
+
+            $str.=';' . $param->serialize();
+
+        }
+
+        $src = array(
+            '\\',
+            "\n",
+            "\r",
+        );
+        $out = array(
+            '\\\\',
+            '\n',
+            '',
+        );
+        $str.=':' . str_replace($src, $out, $this->value);
+
+        $out = '';
+        while(strlen($str)>0) {
+            if (strlen($str)>75) {
+                $out.= mb_strcut($str,0,75,'utf-8') . "\r\n";
+                $str = ' ' . mb_strcut($str,75,strlen($str),'utf-8');
+            } else {
+                $out.=$str . "\r\n";
+                $str='';
+                break;
+            }
+        }
+
+        return $out;
+
+    }
+
+    /**
+     * Adds a new componenten or element
+     *
+     * You can call this method with the following syntaxes:
+     *
+     * add(Parameter $element)
+     * add(string $name, $value)
+     *
+     * The first version adds an Parameter
+     * The second adds a property as a string.
+     *
+     * @param mixed $item
+     * @param mixed $itemValue
+     * @return void
+     */
+    public function add($item, $itemValue = null) {
+
+        if ($item instanceof Parameter) {
+            if (!is_null($itemValue)) {
+                throw new \InvalidArgumentException('The second argument must not be specified, when passing a VObject');
+            }
+            $item->parent = $this;
+            $this->parameters[] = $item;
+        } elseif(is_string($item)) {
+
+            $parameter = new Parameter($item,$itemValue);
+            $parameter->parent = $this;
+            $this->parameters[] = $parameter;
+
+        } else {
+
+            throw new \InvalidArgumentException('The first argument must either be a Node a string');
+
+        }
+
+    }
+
+    /* ArrayAccess interface {{{ */
+
+    /**
+     * Checks if an array element exists
+     *
+     * @param mixed $name
+     * @return bool
+     */
+    public function offsetExists($name) {
+
+        if (is_int($name)) return parent::offsetExists($name);
+
+        $name = strtoupper($name);
+
+        foreach($this->parameters as $parameter) {
+            if ($parameter->name == $name) return true;
+        }
+        return false;
+
+    }
+
+    /**
+     * Returns a parameter, or parameter list.
+     *
+     * @param string $name
+     * @return Node
+     */
+    public function offsetGet($name) {
+
+        if (is_int($name)) return parent::offsetGet($name);
+        $name = strtoupper($name);
+
+        $result = array();
+        foreach($this->parameters as $parameter) {
+            if ($parameter->name == $name)
+                $result[] = $parameter;
+        }
+
+        if (count($result)===0) {
+            return null;
+        } elseif (count($result)===1) {
+            return $result[0];
+        } else {
+            $result[0]->setIterator(new ElementList($result));
+            return $result[0];
+        }
+
+    }
+
+    /**
+     * Creates a new parameter
+     *
+     * @param string $name
+     * @param mixed $value
+     * @return void
+     */
+    public function offsetSet($name, $value) {
+
+        if (is_int($name)) parent::offsetSet($name, $value);
+
+        if (is_scalar($value)) {
+            if (!is_string($name))
+                throw new \InvalidArgumentException('A parameter name must be specified. This means you cannot use the $array[]="string" to add parameters.');
+
+            $this->offsetUnset($name);
+            $parameter = new Parameter($name, $value);
+            $parameter->parent = $this;
+            $this->parameters[] = $parameter;
+
+        } elseif ($value instanceof Parameter) {
+            if (!is_null($name))
+                throw new \InvalidArgumentException('Don\'t specify a parameter name if you\'re passing a \\Sabre\\VObject\\Parameter. Add using $array[]=$parameterObject.');
+
+            $value->parent = $this;
+            $this->parameters[] = $value;
+        } else {
+            throw new \InvalidArgumentException('You can only add parameters to the property object');
+        }
+
+    }
+
+    /**
+     * Removes one or more parameters with the specified name
+     *
+     * @param string $name
+     * @return void
+     */
+    public function offsetUnset($name) {
+
+        if (is_int($name)) parent::offsetUnset($name);
+        $name = strtoupper($name);
+
+        foreach($this->parameters as $key=>$parameter) {
+            if ($parameter->name == $name) {
+                $parameter->parent = null;
+                unset($this->parameters[$key]);
+            }
+
+        }
+
+    }
+
+    /* }}} */
+
+    /**
+     * Called when this object is being cast to a string
+     *
+     * @return string
+     */
+    public function __toString() {
+
+        return (string)$this->value;
+
+    }
+
+    /**
+     * This method is automatically called when the object is cloned.
+     * Specifically, this will ensure all child elements are also cloned.
+     *
+     * @return void
+     */
+    public function __clone() {
+
+        foreach($this->parameters as $key=>$child) {
+            $this->parameters[$key] = clone $child;
+            $this->parameters[$key]->parent = $this;
+        }
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   - Node::REPAIR - If something is broken, and automatic repair may
+     *                    be attempted.
+     *
+     * An array is returned with warnings.
+     *
+     * Every item in the array has the following properties:
+     *    * level - (number between 1 and 3 with severity information)
+     *    * message - (human readable message)
+     *    * node - (reference to the offending node)
+     *
+     * @param int $options
+     * @return array
+     */
+    public function validate($options = 0) {
+
+        $warnings = array();
+
+        // Checking if our value is UTF-8
+        if (!StringUtil::isUTF8($this->value)) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'Property is not valid UTF-8!',
+                'node' => $this,
+            );
+            if ($options & self::REPAIR) {
+                $this->value = StringUtil::convertToUTF8($this->value);
+            }
+        }
+
+        // Checking if the propertyname does not contain any invalid bytes.
+        if (!preg_match('/^([A-Z0-9-]+)$/', $this->name)) {
+            $warnings[] = array(
+                'level' => 1,
+                'message' => 'The propertyname: ' . $this->name . ' contains invalid characters. Only A-Z, 0-9 and - are allowed',
+                'node' => $this,
+            );
+            if ($options & self::REPAIR) {
+                // Uppercasing and converting underscores to dashes.
+                $this->name = strtoupper(
+                    str_replace('_', '-', $this->name)
+                );
+                // Removing every other invalid character
+                $this->name = preg_replace('/([^A-Z0-9-])/u', '', $this->name);
+
+            }
+
+        }
+
+        // Validating inner parameters
+        foreach($this->parameters as $param) {
+            $warnings = array_merge($warnings, $param->validate($options));
+        }
+
+        return $warnings;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Property/Compound.php b/vendor/sabre/vobject/lib/Sabre/VObject/Property/Compound.php
new file mode 100644
index 000000000..26f090069
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Property/Compound.php
@@ -0,0 +1,125 @@
+<?php
+
+namespace Sabre\VObject\Property;
+
+use Sabre\VObject;
+
+/**
+ * Compound property.
+ *
+ * This class adds (de)serialization of compound properties to/from arrays.
+ *
+ * Currently the following properties from RFC 6350 are mapped to use this
+ * class:
+ *
+ *  N:          Section 6.2.2
+ *  ADR:        Section 6.3.1
+ *  ORG:        Section 6.6.4
+ *  CATEGORIES: Section 6.7.1
+ *
+ * In order to use this correctly, you must call setParts and getParts to
+ * retrieve and modify dates respectively.
+ *
+ * @author Thomas Tanghus (http://tanghus.net/)
+ * @author Lars Kneschke
+ * @author Evert Pot (http://evertpot.com/)
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Compound extends VObject\Property {
+
+    /**
+     * If property names are added to this map, they will be (de)serialised as arrays
+     * using the getParts() and setParts() methods.
+     * The keys are the property names, values are delimiter chars.
+     *
+     * @var array
+     */
+    static public $delimiterMap = array(
+        'N'           =>    ';',
+        'ADR'         =>    ';',
+        'ORG'         =>    ';',
+        'CATEGORIES'  =>    ',',
+    );
+
+    /**
+     * The currently used delimiter.
+     *
+     * @var string
+     */
+    protected $delimiter = null;
+
+    /**
+     * Get a compound value as an array.
+     *
+     * @param $name string
+     * @return array
+     */
+    public function getParts() {
+
+        if (is_null($this->value)) {
+            return array();
+        }
+
+        $delimiter = $this->getDelimiter();
+
+        // split by any $delimiter which is NOT prefixed by a slash.
+        // Note that this is not a a perfect solution. If a value is prefixed
+        // by two slashes, it should actually be split anyway.
+        //
+        // Hopefully we can fix this better in a future version, where we can
+        // break compatibility a bit.
+        $compoundValues = preg_split("/(?<!\\\)$delimiter/", $this->value);
+
+        // remove slashes from any semicolon and comma left escaped in the single values
+        $compoundValues = array_map(
+            function($val) {
+                return strtr($val, array('\,' => ',', '\;' => ';'));
+        }, $compoundValues);
+
+        return $compoundValues;
+
+    }
+
+    /**
+     * Returns the delimiter for this property.
+     *
+     * @return string
+     */
+    public function getDelimiter() {
+
+        if (!$this->delimiter) {
+            if (isset(self::$delimiterMap[$this->name])) {
+                $this->delimiter = self::$delimiterMap[$this->name];
+            } else {
+                // To be a bit future proof, we are going to default the
+                // delimiter to ;
+                $this->delimiter = ';';
+            }
+        }
+        return $this->delimiter;
+
+    }
+
+    /**
+     * Set a compound value as an array.
+     *
+     *
+     * @param $name string
+     * @return array
+     */
+    public function setParts(array $values) {
+
+        // add slashes to all semicolons and commas in the single values
+        $values = array_map(
+            function($val) {
+                return strtr($val, array(',' => '\,', ';' => '\;'));
+            }, $values);
+
+        $this->setValue(
+            implode($this->getDelimiter(), $values)
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Property/DateTime.php b/vendor/sabre/vobject/lib/Sabre/VObject/Property/DateTime.php
new file mode 100644
index 000000000..95e9b0209
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Property/DateTime.php
@@ -0,0 +1,245 @@
+<?php
+
+namespace Sabre\VObject\Property;
+
+use Sabre\VObject;
+
+/**
+ * DateTime property
+ *
+ * This element is used for iCalendar properties such as the DTSTART property.
+ * It basically provides a few helper functions that make it easier to deal
+ * with these. It supports both DATE-TIME and DATE values.
+ *
+ * In order to use this correctly, you must call setDateTime and getDateTime to
+ * retrieve and modify dates respectively.
+ *
+ * If you use the 'value' or properties directly, this object does not keep
+ * reference and results might appear incorrectly.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class DateTime extends VObject\Property {
+
+    /**
+     * Local 'floating' time
+     */
+    const LOCAL = 1;
+
+    /**
+     * UTC-based time
+     */
+    const UTC = 2;
+
+    /**
+     * Local time plus timezone
+     */
+    const LOCALTZ = 3;
+
+    /**
+     * Only a date, time is ignored
+     */
+    const DATE = 4;
+
+    /**
+     * DateTime representation
+     *
+     * @var \DateTime
+     */
+    protected $dateTime;
+
+    /**
+     * dateType
+     *
+     * @var int
+     */
+    protected $dateType;
+
+    /**
+     * Updates the Date and Time.
+     *
+     * @param \DateTime $dt
+     * @param int $dateType
+     * @return void
+     */
+    public function setDateTime(\DateTime $dt, $dateType = self::LOCALTZ) {
+
+        switch($dateType) {
+
+            case self::LOCAL :
+                $this->setValue($dt->format('Ymd\\THis'));
+                $this->offsetUnset('VALUE');
+                $this->offsetUnset('TZID');
+                $this->offsetSet('VALUE','DATE-TIME');
+                break;
+            case self::UTC :
+                $dt->setTimeZone(new \DateTimeZone('UTC'));
+                $this->setValue($dt->format('Ymd\\THis\\Z'));
+                $this->offsetUnset('VALUE');
+                $this->offsetUnset('TZID');
+                $this->offsetSet('VALUE','DATE-TIME');
+                break;
+            case self::LOCALTZ :
+                $this->setValue($dt->format('Ymd\\THis'));
+                $this->offsetUnset('VALUE');
+                $this->offsetUnset('TZID');
+                $this->offsetSet('VALUE','DATE-TIME');
+                $this->offsetSet('TZID', $dt->getTimeZone()->getName());
+                break;
+            case self::DATE :
+                $this->setValue($dt->format('Ymd'));
+                $this->offsetUnset('VALUE');
+                $this->offsetUnset('TZID');
+                $this->offsetSet('VALUE','DATE');
+                break;
+            default :
+                throw new \InvalidArgumentException('You must pass a valid dateType constant');
+
+        }
+        $this->dateTime = $dt;
+        $this->dateType = $dateType;
+
+    }
+
+    /**
+     * Returns the current DateTime value.
+     *
+     * If no value was set, this method returns null.
+     *
+     * @return \DateTime|null
+     */
+    public function getDateTime() {
+
+        if ($this->dateTime)
+            return $this->dateTime;
+
+        list(
+            $this->dateType,
+            $this->dateTime
+        ) = self::parseData($this->value, $this);
+        return $this->dateTime;
+
+    }
+
+    /**
+     * Returns the type of Date format.
+     *
+     * This method returns one of the format constants. If no date was set,
+     * this method will return null.
+     *
+     * @return int|null
+     */
+    public function getDateType() {
+
+        if ($this->dateType)
+            return $this->dateType;
+
+        list(
+            $this->dateType,
+            $this->dateTime,
+        ) = self::parseData($this->value, $this);
+        return $this->dateType;
+
+    }
+
+    /**
+     * This method will return true, if the property had a date and a time, as
+     * opposed to only a date.
+     *
+     * @return bool
+     */
+    public function hasTime() {
+
+        return $this->getDateType()!==self::DATE;
+
+    }
+
+    /**
+     * Parses the internal data structure to figure out what the current date
+     * and time is.
+     *
+     * The returned array contains two elements:
+     *   1. A 'DateType' constant (as defined on this class), or null.
+     *   2. A DateTime object (or null)
+     *
+     * @param string|null $propertyValue The string to parse (yymmdd or
+     *                                   ymmddThhmmss, etc..)
+     * @param \Sabre\VObject\Property|null $property The instance of the
+     *                                              property we're parsing.
+     * @return array
+     */
+    static public function parseData($propertyValue, VObject\Property $property = null) {
+
+        if (is_null($propertyValue)) {
+            return array(null, null);
+        }
+
+        $date = '(?P<year>[1-2][0-9]{3})(?P<month>[0-1][0-9])(?P<date>[0-3][0-9])';
+        $time = '(?P<hour>[0-2][0-9])(?P<minute>[0-5][0-9])(?P<second>[0-5][0-9])';
+        $regex = "/^$date(T$time(?P<isutc>Z)?)?$/";
+
+        if (!preg_match($regex, $propertyValue, $matches)) {
+            throw new \InvalidArgumentException($propertyValue . ' is not a valid \DateTime or Date string');
+        }
+
+        if (!isset($matches['hour'])) {
+            // Date-only
+            return array(
+                self::DATE,
+                new \DateTime($matches['year'] . '-' . $matches['month'] . '-' . $matches['date'] . ' 00:00:00', new \DateTimeZone('UTC')),
+            );
+        }
+
+        $dateStr =
+            $matches['year'] .'-' .
+            $matches['month'] . '-' .
+            $matches['date'] . ' ' .
+            $matches['hour'] . ':' .
+            $matches['minute'] . ':' .
+            $matches['second'];
+
+        if (isset($matches['isutc'])) {
+            $dt = new \DateTime($dateStr,new \DateTimeZone('UTC'));
+            $dt->setTimeZone(new \DateTimeZone('UTC'));
+            return array(
+                self::UTC,
+                $dt
+            );
+        }
+
+        // Finding the timezone.
+        $tzid = $property['TZID'];
+        if (!$tzid) {
+            // This was a floating time string. This implies we use the
+            // timezone from date_default_timezone_set / date.timezone ini
+            // setting.
+            return array(
+                self::LOCAL,
+                new \DateTime($dateStr)
+            );
+        }
+
+        // To look up the timezone, we must first find the VCALENDAR component.
+        $root = $property;
+        while($root->parent) {
+            $root = $root->parent;
+        }
+        if ($root->name === 'VCALENDAR') {
+            $tz = VObject\TimeZoneUtil::getTimeZone((string)$tzid, $root);
+        } else {
+            $tz = VObject\TimeZoneUtil::getTimeZone((string)$tzid);
+        }
+
+        $dt = new \DateTime($dateStr, $tz);
+        $dt->setTimeZone($tz);
+
+        return array(
+            self::LOCALTZ,
+            $dt
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Property/MultiDateTime.php b/vendor/sabre/vobject/lib/Sabre/VObject/Property/MultiDateTime.php
new file mode 100644
index 000000000..f01491b66
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Property/MultiDateTime.php
@@ -0,0 +1,180 @@
+<?php
+
+namespace Sabre\VObject\Property;
+
+use Sabre\VObject;
+
+/**
+ * Multi-DateTime property
+ *
+ * This element is used for iCalendar properties such as the EXDATE property.
+ * It basically provides a few helper functions that make it easier to deal
+ * with these. It supports both DATE-TIME and DATE values.
+ *
+ * In order to use this correctly, you must call setDateTimes and getDateTimes
+ * to retrieve and modify dates respectively.
+ *
+ * If you use the 'value' or properties directly, this object does not keep
+ * reference and results might appear incorrectly.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class MultiDateTime extends VObject\Property {
+
+    /**
+     * DateTime representation
+     *
+     * @var DateTime[]
+     */
+    protected $dateTimes;
+
+    /**
+     * dateType
+     *
+     * This is one of the Sabre\VObject\Property\DateTime constants.
+     *
+     * @var int
+     */
+    protected $dateType;
+
+    /**
+     * Updates the value
+     *
+     * @param array $dt Must be an array of DateTime objects.
+     * @param int $dateType
+     * @return void
+     */
+    public function setDateTimes(array $dt, $dateType = VObject\Property\DateTime::LOCALTZ) {
+
+        foreach($dt as $i)
+            if (!$i instanceof \DateTime)
+                throw new \InvalidArgumentException('You must pass an array of DateTime objects');
+
+        $this->offsetUnset('VALUE');
+        $this->offsetUnset('TZID');
+        switch($dateType) {
+
+            case DateTime::LOCAL :
+                $val = array();
+                foreach($dt as $i) {
+                    $val[] = $i->format('Ymd\\THis');
+                }
+                $this->setValue(implode(',',$val));
+                $this->offsetSet('VALUE','DATE-TIME');
+                break;
+            case DateTime::UTC :
+                $val = array();
+                foreach($dt as $i) {
+                    $i->setTimeZone(new \DateTimeZone('UTC'));
+                    $val[] = $i->format('Ymd\\THis\\Z');
+                }
+                $this->setValue(implode(',',$val));
+                $this->offsetSet('VALUE','DATE-TIME');
+                break;
+            case DateTime::LOCALTZ :
+                $val = array();
+                foreach($dt as $i) {
+                    $val[] = $i->format('Ymd\\THis');
+                }
+                $this->setValue(implode(',',$val));
+                $this->offsetSet('VALUE','DATE-TIME');
+                $this->offsetSet('TZID', $dt[0]->getTimeZone()->getName());
+                break;
+            case DateTime::DATE :
+                $val = array();
+                foreach($dt as $i) {
+                    $val[] = $i->format('Ymd');
+                }
+                $this->setValue(implode(',',$val));
+                $this->offsetSet('VALUE','DATE');
+                break;
+            default :
+                throw new \InvalidArgumentException('You must pass a valid dateType constant');
+
+        }
+        $this->dateTimes = $dt;
+        $this->dateType = $dateType;
+
+    }
+
+    /**
+     * Returns the current DateTime value.
+     *
+     * If no value was set, this method returns null.
+     *
+     * @return array|null
+     */
+    public function getDateTimes() {
+
+        if ($this->dateTimes)
+            return $this->dateTimes;
+
+        $dts = array();
+
+        if (!$this->value) {
+            $this->dateTimes = null;
+            $this->dateType = null;
+            return null;
+        }
+
+        foreach(explode(',',$this->value) as $val) {
+            list(
+                $type,
+                $dt
+            ) = DateTime::parseData($val, $this);
+            $dts[] = $dt;
+            $this->dateType = $type;
+        }
+        $this->dateTimes = $dts;
+        return $this->dateTimes;
+
+    }
+
+    /**
+     * Returns the type of Date format.
+     *
+     * This method returns one of the format constants. If no date was set,
+     * this method will return null.
+     *
+     * @return int|null
+     */
+    public function getDateType() {
+
+        if ($this->dateType)
+            return $this->dateType;
+
+        if (!$this->value) {
+            $this->dateTimes = null;
+            $this->dateType = null;
+            return null;
+        }
+
+        $dts = array();
+        foreach(explode(',',$this->value) as $val) {
+            list(
+                $type,
+                $dt
+            ) = DateTime::parseData($val, $this);
+            $dts[] = $dt;
+            $this->dateType = $type;
+        }
+        $this->dateTimes = $dts;
+        return $this->dateType;
+
+    }
+
+    /**
+     * This method will return true, if the property had a date and a time, as
+     * opposed to only a date.
+     *
+     * @return bool
+     */
+    public function hasTime() {
+
+        return $this->getDateType()!==DateTime::DATE;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Reader.php b/vendor/sabre/vobject/lib/Sabre/VObject/Reader.php
new file mode 100644
index 000000000..a001b2bf1
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Reader.php
@@ -0,0 +1,223 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VCALENDAR/VCARD reader
+ *
+ * This class reads the vobject file, and returns a full element tree.
+ *
+ * TODO: this class currently completely works 'statically'. This is pointless,
+ * and defeats OOP principals. Needs refactoring in a future version.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Reader {
+
+    /**
+     * If this option is passed to the reader, it will be less strict about the
+     * validity of the lines.
+     *
+     * Currently using this option just means, that it will accept underscores
+     * in property names.
+     */
+    const OPTION_FORGIVING = 1;
+
+    /**
+     * If this option is turned on, any lines we cannot parse will be ignored
+     * by the reader.
+     */
+    const OPTION_IGNORE_INVALID_LINES = 2;
+
+    /**
+     * Parses the file and returns the top component
+     *
+     * The options argument is a bitfield. Pass any of the OPTIONS constant to
+     * alter the parsers' behaviour.
+     *
+     * @param string $data
+     * @param int $options
+     * @return Node
+     */
+    static function read($data, $options = 0) {
+
+        // Normalizing newlines
+        $data = str_replace(array("\r","\n\n"), array("\n","\n"), $data);
+
+        $lines = explode("\n", $data);
+
+        // Unfolding lines
+        $lines2 = array();
+        foreach($lines as $line) {
+
+            // Skipping empty lines
+            if (!$line) continue;
+
+            if ($line[0]===" " || $line[0]==="\t") {
+                $lines2[count($lines2)-1].=substr($line,1);
+            } else {
+                $lines2[] = $line;
+            }
+
+        }
+
+        unset($lines);
+
+        reset($lines2);
+
+        return self::readLine($lines2, $options);
+
+    }
+
+    /**
+     * Reads and parses a single line.
+     *
+     * This method receives the full array of lines. The array pointer is used
+     * to traverse.
+     *
+     * This method returns null if an invalid line was encountered, and the
+     * IGNORE_INVALID_LINES option was turned on.
+     *
+     * @param array $lines
+     * @param int $options See the OPTIONS constants.
+     * @return Node
+     */
+    static private function readLine(&$lines, $options = 0) {
+
+        $line = current($lines);
+        $lineNr = key($lines);
+        next($lines);
+
+        // Components
+        if (strtoupper(substr($line,0,6)) === "BEGIN:") {
+
+            $componentName = strtoupper(substr($line,6));
+            $obj = Component::create($componentName);
+
+            $nextLine = current($lines);
+
+            while(strtoupper(substr($nextLine,0,4))!=="END:") {
+
+                $parsedLine = self::readLine($lines, $options);
+                $nextLine = current($lines);
+
+                if (is_null($parsedLine)) {
+                    continue;
+                }
+                $obj->add($parsedLine);
+
+                if ($nextLine===false)
+                    throw new ParseException('Invalid VObject. Document ended prematurely.');
+
+            }
+
+            // Checking component name of the 'END:' line.
+            if (substr($nextLine,4)!==$obj->name) {
+                throw new ParseException('Invalid VObject, expected: "END:' . $obj->name . '" got: "' . $nextLine . '"');
+            }
+            next($lines);
+
+            return $obj;
+
+        }
+
+        // Properties
+        //$result = preg_match('/(?P<name>[A-Z0-9-]+)(?:;(?P<parameters>^(?<!:):))(.*)$/',$line,$matches);
+
+        if ($options & self::OPTION_FORGIVING) {
+            $token = '[A-Z0-9-\._]+';
+        } else {
+            $token = '[A-Z0-9-\.]+';
+        }
+        $parameters = "(?:;(?P<parameters>([^:^\"]|\"([^\"]*)\")*))?";
+        $regex = "/^(?P<name>$token)$parameters:(?P<value>.*)$/i";
+
+        $result = preg_match($regex,$line,$matches);
+
+        if (!$result) {
+            if ($options & self::OPTION_IGNORE_INVALID_LINES) {
+                return null;
+            } else {
+                throw new ParseException('Invalid VObject, line ' . ($lineNr+1) . ' did not follow the icalendar/vcard format');
+            }
+        }
+
+        $propertyName = strtoupper($matches['name']);
+        $propertyValue = preg_replace_callback('#(\\\\(\\\\|N|n))#',function($matches) {
+            if ($matches[2]==='n' || $matches[2]==='N') {
+                return "\n";
+            } else {
+                return $matches[2];
+            }
+        }, $matches['value']);
+
+        $obj = Property::create($propertyName, $propertyValue);
+
+        if ($matches['parameters']) {
+
+            foreach(self::readParameters($matches['parameters']) as $param) {
+                $obj->add($param);
+            }
+
+        }
+
+        return $obj;
+
+
+    }
+
+    /**
+     * Reads a parameter list from a property
+     *
+     * This method returns an array of Parameter
+     *
+     * @param string $parameters
+     * @return array
+     */
+    static private function readParameters($parameters) {
+
+        $token = '[A-Z0-9-]+';
+
+        $paramValue = '(?P<paramValue>[^\"^;]*|"[^"]*")';
+
+        $regex = "/(?<=^|;)(?P<paramName>$token)(=$paramValue(?=$|;))?/i";
+        preg_match_all($regex, $parameters, $matches,  PREG_SET_ORDER);
+
+        $params = array();
+        foreach($matches as $match) {
+
+            if (!isset($match['paramValue'])) {
+
+                $value = null;
+
+            } else {
+
+                $value = $match['paramValue'];
+
+                if (isset($value[0]) && $value[0]==='"') {
+                    // Stripping quotes, if needed
+                    $value = substr($value,1,strlen($value)-2);
+                }
+
+                $value = preg_replace_callback('#(\\\\(\\\\|N|n|;|,))#',function($matches) {
+                    if ($matches[2]==='n' || $matches[2]==='N') {
+                        return "\n";
+                    } else {
+                        return $matches[2];
+                    }
+                }, $value);
+
+            }
+
+            $params[] = new Parameter($match['paramName'], $value);
+
+        }
+
+        return $params;
+
+    }
+
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/RecurrenceIterator.php b/vendor/sabre/vobject/lib/Sabre/VObject/RecurrenceIterator.php
new file mode 100644
index 000000000..8bd4ed224
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/RecurrenceIterator.php
@@ -0,0 +1,1144 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * This class is used to determine new for a recurring event, when the next
+ * events occur.
+ *
+ * This iterator may loop infinitely in the future, therefore it is important
+ * that if you use this class, you set hard limits for the amount of iterations
+ * you want to handle.
+ *
+ * Note that currently there is not full support for the entire iCalendar
+ * specification, as it's very complex and contains a lot of permutations
+ * that's not yet used very often in software.
+ *
+ * For the focus has been on features as they actually appear in Calendaring
+ * software, but this may well get expanded as needed / on demand
+ *
+ * The following RRULE properties are supported
+ *   * UNTIL
+ *   * INTERVAL
+ *   * COUNT
+ *   * FREQ=DAILY
+ *     * BYDAY
+ *     * BYHOUR
+ *   * FREQ=WEEKLY
+ *     * BYDAY
+ *     * BYHOUR
+ *     * WKST
+ *   * FREQ=MONTHLY
+ *     * BYMONTHDAY
+ *     * BYDAY
+ *     * BYSETPOS
+ *   * FREQ=YEARLY
+ *     * BYMONTH
+ *     * BYMONTHDAY (only if BYMONTH is also set)
+ *     * BYDAY (only if BYMONTH is also set)
+ *
+ * Anything beyond this is 'undefined', which means that it may get ignored, or
+ * you may get unexpected results. The effect is that in some applications the
+ * specified recurrence may look incorrect, or is missing.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class RecurrenceIterator implements \Iterator {
+
+    /**
+     * The initial event date
+     *
+     * @var DateTime
+     */
+    public $startDate;
+
+    /**
+     * The end-date of the initial event
+     *
+     * @var DateTime
+     */
+    public $endDate;
+
+    /**
+     * The 'current' recurrence.
+     *
+     * This will be increased for every iteration.
+     *
+     * @var DateTime
+     */
+    public $currentDate;
+
+
+    /**
+     * List of dates that are excluded from the rules.
+     *
+     * This list contains the items that have been overriden by the EXDATE
+     * property.
+     *
+     * @var array
+     */
+    public $exceptionDates = array();
+
+    /**
+     * Base event
+     *
+     * @var Component\VEvent
+     */
+    public $baseEvent;
+
+    /**
+     * List of dates that are overridden by other events.
+     * Similar to $overriddenEvents, but this just contains the original dates.
+     *
+     * @var array
+     */
+    public $overriddenDates = array();
+
+    /**
+     * list of events that are 'overridden'.
+     *
+     * This is an array of Component\VEvent objects.
+     *
+     * @var array
+     */
+    public $overriddenEvents = array();
+
+    /**
+     * Frequency is one of: secondly, minutely, hourly, daily, weekly, monthly,
+     * yearly.
+     *
+     * @var string
+     */
+    public $frequency;
+
+    /**
+     * The last instance of this recurrence, inclusively
+     *
+     * @var DateTime|null
+     */
+    public $until;
+
+    /**
+     * The number of recurrences, or 'null' if infinitely recurring.
+     *
+     * @var int
+     */
+    public $count;
+
+    /**
+     * The interval.
+     *
+     * If for example frequency is set to daily, interval = 2 would mean every
+     * 2 days.
+     *
+     * @var int
+     */
+    public $interval = 1;
+
+    /**
+     * Which seconds to recur.
+     *
+     * This is an array of integers (between 0 and 60)
+     *
+     * @var array
+     */
+    public $bySecond;
+
+    /**
+     * Which minutes to recur
+     *
+     * This is an array of integers (between 0 and 59)
+     *
+     * @var array
+     */
+    public $byMinute;
+
+    /**
+     * Which hours to recur
+     *
+     * This is an array of integers (between 0 and 23)
+     *
+     * @var array
+     */
+    public $byHour;
+
+    /**
+     * Which weekdays to recur.
+     *
+     * This is an array of weekdays
+     *
+     * This may also be preceeded by a positive or negative integer. If present,
+     * this indicates the nth occurrence of a specific day within the monthly or
+     * yearly rrule. For instance, -2TU indicates the second-last tuesday of
+     * the month, or year.
+     *
+     * @var array
+     */
+    public $byDay;
+
+    /**
+     * Which days of the month to recur
+     *
+     * This is an array of days of the months (1-31). The value can also be
+     * negative. -5 for instance means the 5th last day of the month.
+     *
+     * @var array
+     */
+    public $byMonthDay;
+
+    /**
+     * Which days of the year to recur.
+     *
+     * This is an array with days of the year (1 to 366). The values can also
+     * be negative. For instance, -1 will always represent the last day of the
+     * year. (December 31st).
+     *
+     * @var array
+     */
+    public $byYearDay;
+
+    /**
+     * Which week numbers to recur.
+     *
+     * This is an array of integers from 1 to 53. The values can also be
+     * negative. -1 will always refer to the last week of the year.
+     *
+     * @var array
+     */
+    public $byWeekNo;
+
+    /**
+     * Which months to recur
+     *
+     * This is an array of integers from 1 to 12.
+     *
+     * @var array
+     */
+    public $byMonth;
+
+    /**
+     * Which items in an existing st to recur.
+     *
+     * These numbers work together with an existing by* rule. It specifies
+     * exactly which items of the existing by-rule to filter.
+     *
+     * Valid values are 1 to 366 and -1 to -366. As an example, this can be
+     * used to recur the last workday of the month.
+     *
+     * This would be done by setting frequency to 'monthly', byDay to
+     * 'MO,TU,WE,TH,FR' and bySetPos to -1.
+     *
+     * @var array
+     */
+    public $bySetPos;
+
+    /**
+     * When a week starts
+     *
+     * @var string
+     */
+    public $weekStart = 'MO';
+
+    /**
+     * The current item in the list
+     *
+     * @var int
+     */
+    public $counter = 0;
+
+    /**
+     * Simple mapping from iCalendar day names to day numbers
+     *
+     * @var array
+     */
+    private $dayMap = array(
+        'SU' => 0,
+        'MO' => 1,
+        'TU' => 2,
+        'WE' => 3,
+        'TH' => 4,
+        'FR' => 5,
+        'SA' => 6,
+    );
+
+    /**
+     * Mappings between the day number and english day name.
+     *
+     * @var array
+     */
+    private $dayNames = array(
+        0 => 'Sunday',
+        1 => 'Monday',
+        2 => 'Tuesday',
+        3 => 'Wednesday',
+        4 => 'Thursday',
+        5 => 'Friday',
+        6 => 'Saturday',
+    );
+
+    /**
+     * If the current iteration of the event is an overriden event, this
+     * property will hold the VObject
+     *
+     * @var Component
+     */
+    private $currentOverriddenEvent;
+
+    /**
+     * This property may contain the date of the next not-overridden event.
+     * This date is calculated sometimes a bit early, before overridden events
+     * are evaluated.
+     *
+     * @var DateTime
+     */
+    private $nextDate;
+
+    /**
+     * This counts the number of overridden events we've handled so far
+     *
+     * @var int
+     */
+    private $handledOverridden = 0;
+
+    /**
+     * Creates the iterator
+     *
+     * You should pass a VCALENDAR component, as well as the UID of the event
+     * we're going to traverse.
+     *
+     * @param Component $vcal
+     * @param string|null $uid
+     */
+    public function __construct(Component $vcal, $uid=null) {
+
+        if (is_null($uid)) {
+            if ($vcal->name === 'VCALENDAR') {
+                throw new \InvalidArgumentException('If you pass a VCALENDAR object, you must pass a uid argument as well');
+            }
+            $components = array($vcal);
+            $uid = (string)$vcal->uid;
+        } else {
+            $components = $vcal->select('VEVENT');
+        }
+        foreach($components as $component) {
+            if ((string)$component->uid == $uid) {
+                if (isset($component->{'RECURRENCE-ID'})) {
+                    $this->overriddenEvents[$component->DTSTART->getDateTime()->getTimeStamp()] = $component;
+                    $this->overriddenDates[] = $component->{'RECURRENCE-ID'}->getDateTime();
+                } else {
+                    $this->baseEvent = $component;
+                }
+            }
+        }
+
+        ksort($this->overriddenEvents);
+
+        if (!$this->baseEvent) {
+            throw new \InvalidArgumentException('Could not find a base event with uid: ' . $uid);
+        }
+
+        $this->startDate = clone $this->baseEvent->DTSTART->getDateTime();
+
+        $this->endDate = null;
+        if (isset($this->baseEvent->DTEND)) {
+            $this->endDate = clone $this->baseEvent->DTEND->getDateTime();
+        } else {
+            $this->endDate = clone $this->startDate;
+            if (isset($this->baseEvent->DURATION)) {
+                $this->endDate->add(DateTimeParser::parse($this->baseEvent->DURATION->value));
+            } elseif ($this->baseEvent->DTSTART->getDateType()===Property\DateTime::DATE) {
+                $this->endDate->modify('+1 day');
+            }
+        }
+        $this->currentDate = clone $this->startDate;
+
+        $rrule = (string)$this->baseEvent->RRULE;
+
+        $parts = explode(';', $rrule);
+
+        // If no rrule was specified, we create a default setting
+        if (!$rrule) {
+            $this->frequency = 'daily';
+            $this->count = 1;
+        } else foreach($parts as $part) {
+
+            list($key, $value) = explode('=', $part, 2);
+
+            switch(strtoupper($key)) {
+
+                case 'FREQ' :
+                    if (!in_array(
+                        strtolower($value),
+                        array('secondly','minutely','hourly','daily','weekly','monthly','yearly')
+                    )) {
+                        throw new \InvalidArgumentException('Unknown value for FREQ=' . strtoupper($value));
+
+                    }
+                    $this->frequency = strtolower($value);
+                    break;
+
+                case 'UNTIL' :
+                    $this->until = DateTimeParser::parse($value);
+
+                    // In some cases events are generated with an UNTIL=
+                    // parameter before the actual start of the event.
+                    //
+                    // Not sure why this is happening. We assume that the
+                    // intention was that the event only recurs once.
+                    //
+                    // So we are modifying the parameter so our code doesn't
+                    // break.
+                    if($this->until < $this->baseEvent->DTSTART->getDateTime()) {
+                        $this->until = $this->baseEvent->DTSTART->getDateTime();
+                    }
+                    break;
+
+                case 'COUNT' :
+                    $this->count = (int)$value;
+                    break;
+
+                case 'INTERVAL' :
+                    $this->interval = (int)$value;
+                    if ($this->interval < 1) {
+                        throw new \InvalidArgumentException('INTERVAL in RRULE must be a positive integer!');
+                    }
+                    break;
+
+                case 'BYSECOND' :
+                    $this->bySecond = explode(',', $value);
+                    break;
+
+                case 'BYMINUTE' :
+                    $this->byMinute = explode(',', $value);
+                    break;
+
+                case 'BYHOUR' :
+                    $this->byHour = explode(',', $value);
+                    break;
+
+                case 'BYDAY' :
+                    $this->byDay = explode(',', strtoupper($value));
+                    break;
+
+                case 'BYMONTHDAY' :
+                    $this->byMonthDay = explode(',', $value);
+                    break;
+
+                case 'BYYEARDAY' :
+                    $this->byYearDay = explode(',', $value);
+                    break;
+
+                case 'BYWEEKNO' :
+                    $this->byWeekNo = explode(',', $value);
+                    break;
+
+                case 'BYMONTH' :
+                    $this->byMonth = explode(',', $value);
+                    break;
+
+                case 'BYSETPOS' :
+                    $this->bySetPos = explode(',', $value);
+                    break;
+
+                case 'WKST' :
+                    $this->weekStart = strtoupper($value);
+                    break;
+
+            }
+
+        }
+
+        // Parsing exception dates
+        if (isset($this->baseEvent->EXDATE)) {
+            foreach($this->baseEvent->EXDATE as $exDate) {
+
+                foreach(explode(',', (string)$exDate) as $exceptionDate) {
+
+                    $this->exceptionDates[] =
+                        DateTimeParser::parse($exceptionDate, $this->startDate->getTimeZone());
+
+                }
+
+            }
+
+        }
+
+    }
+
+    /**
+     * Returns the current item in the list
+     *
+     * @return DateTime
+     */
+    public function current() {
+
+        if (!$this->valid()) return null;
+        return clone $this->currentDate;
+
+    }
+
+    /**
+     * This method returns the startdate for the current iteration of the
+     * event.
+     *
+     * @return DateTime
+     */
+    public function getDtStart() {
+
+        if (!$this->valid()) return null;
+        return clone $this->currentDate;
+
+    }
+
+    /**
+     * This method returns the enddate for the current iteration of the
+     * event.
+     *
+     * @return DateTime
+     */
+    public function getDtEnd() {
+
+        if (!$this->valid()) return null;
+        $dtEnd = clone $this->currentDate;
+        $dtEnd->add( $this->startDate->diff( $this->endDate ) );
+        return clone $dtEnd;
+
+    }
+
+    /**
+     * Returns a VEVENT object with the updated start and end date.
+     *
+     * Any recurrence information is removed, and this function may return an
+     * 'overridden' event instead.
+     *
+     * This method always returns a cloned instance.
+     *
+     * @return Component\VEvent
+     */
+    public function getEventObject() {
+
+        if ($this->currentOverriddenEvent) {
+            return clone $this->currentOverriddenEvent;
+        }
+        $event = clone $this->baseEvent;
+        unset($event->RRULE);
+        unset($event->EXDATE);
+        unset($event->RDATE);
+        unset($event->EXRULE);
+
+        $event->DTSTART->setDateTime($this->getDTStart(), $event->DTSTART->getDateType());
+        if (isset($event->DTEND)) {
+            $event->DTEND->setDateTime($this->getDtEnd(), $event->DTSTART->getDateType());
+        }
+        if ($this->counter > 0) {
+            $event->{'RECURRENCE-ID'} = (string)$event->DTSTART;
+        }
+
+        return $event;
+
+    }
+
+    /**
+     * Returns the current item number
+     *
+     * @return int
+     */
+    public function key() {
+
+        return $this->counter;
+
+    }
+
+    /**
+     * Whether or not there is a 'next item'
+     *
+     * @return bool
+     */
+    public function valid() {
+
+        if (!is_null($this->count)) {
+            return $this->counter < $this->count;
+        }
+        if (!is_null($this->until) && $this->currentDate > $this->until) {
+
+            // Need to make sure there's no overridden events past the
+            // until date.
+            foreach($this->overriddenEvents as $overriddenEvent) {
+
+                if ($overriddenEvent->DTSTART->getDateTime() >= $this->currentDate) {
+
+                    return true;
+                }
+            }
+            return false;
+        }
+        return true;
+
+    }
+
+    /**
+     * Resets the iterator
+     *
+     * @return void
+     */
+    public function rewind() {
+
+        $this->currentDate = clone $this->startDate;
+        $this->counter = 0;
+
+    }
+
+    /**
+     * This method allows you to quickly go to the next occurrence after the
+     * specified date.
+     *
+     * Note that this checks the current 'endDate', not the 'stardDate'. This
+     * means that if you forward to January 1st, the iterator will stop at the
+     * first event that ends *after* January 1st.
+     *
+     * @param DateTime $dt
+     * @return void
+     */
+    public function fastForward(\DateTime $dt) {
+
+        while($this->valid() && $this->getDTEnd() <= $dt) {
+            $this->next();
+        }
+
+    }
+
+    /**
+     * Returns true if this recurring event never ends.
+     *
+     * @return bool
+     */
+    public function isInfinite() {
+
+        return !$this->count && !$this->until;
+
+    }
+
+    /**
+     * Goes on to the next iteration
+     *
+     * @return void
+     */
+    public function next() {
+
+        $previousStamp = $this->currentDate->getTimeStamp();
+
+        // Finding the next overridden event in line, and storing that for
+        // later use.
+        $overriddenEvent = null;
+        $overriddenDate = null;
+        $this->currentOverriddenEvent = null;
+
+        foreach($this->overriddenEvents as $index=>$event) {
+            if ($index > $previousStamp) {
+                $overriddenEvent = $event;
+                $overriddenDate = clone $event->DTSTART->getDateTime();
+                break;
+            }
+        }
+
+        // If we have a stored 'next date', we will use that.
+        if ($this->nextDate) {
+            if (!$overriddenDate || $this->nextDate < $overriddenDate) {
+                $this->currentDate = $this->nextDate;
+                $currentStamp = $this->currentDate->getTimeStamp();
+                $this->nextDate = null;
+            } else {
+                $this->currentDate = clone $overriddenDate;
+                $this->currentOverriddenEvent = $overriddenEvent;
+            }
+            $this->counter++;
+            return;
+        }
+
+        while(true) {
+
+            // Otherwise, we find the next event in the normal RRULE
+            // sequence.
+            switch($this->frequency) {
+
+                case 'hourly' :
+                    $this->nextHourly();
+                    break;
+
+                case 'daily' :
+                    $this->nextDaily();
+                    break;
+
+                case 'weekly' :
+                    $this->nextWeekly();
+                    break;
+
+                case 'monthly' :
+                    $this->nextMonthly();
+                    break;
+
+                case 'yearly' :
+                    $this->nextYearly();
+                    break;
+
+            }
+            $currentStamp = $this->currentDate->getTimeStamp();
+
+
+            // Checking exception dates
+            foreach($this->exceptionDates as $exceptionDate) {
+                if ($this->currentDate == $exceptionDate) {
+                    $this->counter++;
+                    continue 2;
+                }
+            }
+            foreach($this->overriddenDates as $check) {
+                if ($this->currentDate == $check) {
+                    continue 2;
+                }
+            }
+            break;
+
+        }
+
+
+
+        // Is the date we have actually higher than the next overiddenEvent?
+        if ($overriddenDate && $this->currentDate > $overriddenDate) {
+            $this->nextDate = clone $this->currentDate;
+            $this->currentDate = clone $overriddenDate;
+            $this->currentOverriddenEvent = $overriddenEvent;
+            $this->handledOverridden++;
+        }
+        $this->counter++;
+
+
+        /*
+         * If we have overridden events left in the queue, but our counter is
+         * running out, we should grab one of those.
+         */
+        if (!is_null($overriddenEvent) && !is_null($this->count) && count($this->overriddenEvents) - $this->handledOverridden >= ($this->count - $this->counter)) {
+
+            $this->currentOverriddenEvent = $overriddenEvent;
+            $this->currentDate = clone $overriddenDate;
+            $this->handledOverridden++;
+
+        }
+
+    }
+
+    /**
+     * Does the processing for advancing the iterator for hourly frequency.
+     *
+     * @return void
+     */
+    protected function nextHourly() {
+
+        if (!$this->byHour) {
+            $this->currentDate->modify('+' . $this->interval . ' hours');
+            return;
+        }
+    }
+
+    /**
+     * Does the processing for advancing the iterator for daily frequency.
+     *
+     * @return void
+     */
+    protected function nextDaily() {
+
+        if (!$this->byHour && !$this->byDay) {
+            $this->currentDate->modify('+' . $this->interval . ' days');
+            return;
+        }
+
+        if (isset($this->byHour)) {
+            $recurrenceHours = $this->getHours();
+        }
+
+        if (isset($this->byDay)) {
+            $recurrenceDays = $this->getDays();
+        }
+
+        do {
+
+            if ($this->byHour) {
+                if ($this->currentDate->format('G') == '23') {
+                    // to obey the interval rule
+                    $this->currentDate->modify('+' . $this->interval-1 . ' days');
+                }
+
+                $this->currentDate->modify('+1 hours');
+
+            } else {
+                $this->currentDate->modify('+' . $this->interval . ' days');
+
+            }
+
+            // Current day of the week
+            $currentDay = $this->currentDate->format('w');
+
+            // Current hour of the day
+            $currentHour = $this->currentDate->format('G');
+
+        } while (($this->byDay && !in_array($currentDay, $recurrenceDays)) || ($this->byHour && !in_array($currentHour, $recurrenceHours)));
+
+    }
+
+    /**
+     * Does the processing for advancing the iterator for weekly frequency.
+     *
+     * @return void
+     */
+    protected function nextWeekly() {
+
+        if (!$this->byHour && !$this->byDay) {
+            $this->currentDate->modify('+' . $this->interval . ' weeks');
+            return;
+        }
+
+        if ($this->byHour) {
+            $recurrenceHours = $this->getHours();
+        }
+
+        if ($this->byDay) {
+            $recurrenceDays = $this->getDays();
+        }
+
+        // First day of the week:
+        $firstDay = $this->dayMap[$this->weekStart];
+
+        do {
+
+            if ($this->byHour) {
+                $this->currentDate->modify('+1 hours');
+            } else {
+                $this->currentDate->modify('+1 days');
+            }
+
+            // Current day of the week
+            $currentDay = (int) $this->currentDate->format('w');
+
+            // Current hour of the day
+            $currentHour = (int) $this->currentDate->format('G');
+
+            // We need to roll over to the next week
+            if ($currentDay === $firstDay && (!$this->byHour || $currentHour == '0')) {
+                $this->currentDate->modify('+' . $this->interval-1 . ' weeks');
+
+                // We need to go to the first day of this week, but only if we
+                // are not already on this first day of this week.
+                if($this->currentDate->format('w') != $firstDay) {
+                    $this->currentDate->modify('last ' . $this->dayNames[$this->dayMap[$this->weekStart]]);
+                }
+            }
+
+            // We have a match
+        } while (($this->byDay && !in_array($currentDay, $recurrenceDays)) || ($this->byHour && !in_array($currentHour, $recurrenceHours)));
+    }
+
+    /**
+     * Does the processing for advancing the iterator for monthly frequency.
+     *
+     * @return void
+     */
+    protected function nextMonthly() {
+
+        $currentDayOfMonth = $this->currentDate->format('j');
+        if (!$this->byMonthDay && !$this->byDay) {
+
+            // If the current day is higher than the 28th, rollover can
+            // occur to the next month. We Must skip these invalid
+            // entries.
+            if ($currentDayOfMonth < 29) {
+                $this->currentDate->modify('+' . $this->interval . ' months');
+            } else {
+                $increase = 0;
+                do {
+                    $increase++;
+                    $tempDate = clone $this->currentDate;
+                    $tempDate->modify('+ ' . ($this->interval*$increase) . ' months');
+                } while ($tempDate->format('j') != $currentDayOfMonth);
+                $this->currentDate = $tempDate;
+            }
+            return;
+        }
+
+        while(true) {
+
+            $occurrences = $this->getMonthlyOccurrences();
+
+            foreach($occurrences as $occurrence) {
+
+                // The first occurrence thats higher than the current
+                // day of the month wins.
+                if ($occurrence > $currentDayOfMonth) {
+                    break 2;
+                }
+
+            }
+
+            // If we made it all the way here, it means there were no
+            // valid occurrences, and we need to advance to the next
+            // month.
+            $this->currentDate->modify('first day of this month');
+            $this->currentDate->modify('+ ' . $this->interval . ' months');
+
+            // This goes to 0 because we need to start counting at hte
+            // beginning.
+            $currentDayOfMonth = 0;
+
+        }
+
+        $this->currentDate->setDate($this->currentDate->format('Y'), $this->currentDate->format('n'), $occurrence);
+
+    }
+
+    /**
+     * Does the processing for advancing the iterator for yearly frequency.
+     *
+     * @return void
+     */
+    protected function nextYearly() {
+
+        $currentMonth = $this->currentDate->format('n');
+        $currentYear = $this->currentDate->format('Y');
+        $currentDayOfMonth = $this->currentDate->format('j');
+
+        // No sub-rules, so we just advance by year
+        if (!$this->byMonth) {
+
+            // Unless it was a leap day!
+            if ($currentMonth==2 && $currentDayOfMonth==29) {
+
+                $counter = 0;
+                do {
+                    $counter++;
+                    // Here we increase the year count by the interval, until
+                    // we hit a date that's also in a leap year.
+                    //
+                    // We could just find the next interval that's dividable by
+                    // 4, but that would ignore the rule that there's no leap
+                    // year every year that's dividable by a 100, but not by
+                    // 400. (1800, 1900, 2100). So we just rely on the datetime
+                    // functions instead.
+                    $nextDate = clone $this->currentDate;
+                    $nextDate->modify('+ ' . ($this->interval*$counter) . ' years');
+                } while ($nextDate->format('n')!=2);
+                $this->currentDate = $nextDate;
+
+                return;
+
+            }
+
+            // The easiest form
+            $this->currentDate->modify('+' . $this->interval . ' years');
+            return;
+
+        }
+
+        $currentMonth = $this->currentDate->format('n');
+        $currentYear = $this->currentDate->format('Y');
+        $currentDayOfMonth = $this->currentDate->format('j');
+
+        $advancedToNewMonth = false;
+
+        // If we got a byDay or getMonthDay filter, we must first expand
+        // further.
+        if ($this->byDay || $this->byMonthDay) {
+
+            while(true) {
+
+                $occurrences = $this->getMonthlyOccurrences();
+
+                foreach($occurrences as $occurrence) {
+
+                    // The first occurrence that's higher than the current
+                    // day of the month wins.
+                    // If we advanced to the next month or year, the first
+                    // occurrence is always correct.
+                    if ($occurrence > $currentDayOfMonth || $advancedToNewMonth) {
+                        break 2;
+                    }
+
+                }
+
+                // If we made it here, it means we need to advance to
+                // the next month or year.
+                $currentDayOfMonth = 1;
+                $advancedToNewMonth = true;
+                do {
+
+                    $currentMonth++;
+                    if ($currentMonth>12) {
+                        $currentYear+=$this->interval;
+                        $currentMonth = 1;
+                    }
+                } while (!in_array($currentMonth, $this->byMonth));
+
+                $this->currentDate->setDate($currentYear, $currentMonth, $currentDayOfMonth);
+
+            }
+
+            // If we made it here, it means we got a valid occurrence
+            $this->currentDate->setDate($currentYear, $currentMonth, $occurrence);
+            return;
+
+        } else {
+
+            // These are the 'byMonth' rules, if there are no byDay or
+            // byMonthDay sub-rules.
+            do {
+
+                $currentMonth++;
+                if ($currentMonth>12) {
+                    $currentYear+=$this->interval;
+                    $currentMonth = 1;
+                }
+            } while (!in_array($currentMonth, $this->byMonth));
+            $this->currentDate->setDate($currentYear, $currentMonth, $currentDayOfMonth);
+
+            return;
+
+        }
+
+    }
+
+    /**
+     * Returns all the occurrences for a monthly frequency with a 'byDay' or
+     * 'byMonthDay' expansion for the current month.
+     *
+     * The returned list is an array of integers with the day of month (1-31).
+     *
+     * @return array
+     */
+    protected function getMonthlyOccurrences() {
+
+        $startDate = clone $this->currentDate;
+
+        $byDayResults = array();
+
+        // Our strategy is to simply go through the byDays, advance the date to
+        // that point and add it to the results.
+        if ($this->byDay) foreach($this->byDay as $day) {
+
+            $dayName = $this->dayNames[$this->dayMap[substr($day,-2)]];
+
+            // Dayname will be something like 'wednesday'. Now we need to find
+            // all wednesdays in this month.
+            $dayHits = array();
+
+            $checkDate = clone $startDate;
+            $checkDate->modify('first day of this month');
+            $checkDate->modify($dayName);
+
+            do {
+                $dayHits[] = $checkDate->format('j');
+                $checkDate->modify('next ' . $dayName);
+            } while ($checkDate->format('n') === $startDate->format('n'));
+
+            // So now we have 'all wednesdays' for month. It is however
+            // possible that the user only really wanted the 1st, 2nd or last
+            // wednesday.
+            if (strlen($day)>2) {
+                $offset = (int)substr($day,0,-2);
+
+                if ($offset>0) {
+                    // It is possible that the day does not exist, such as a
+                    // 5th or 6th wednesday of the month.
+                    if (isset($dayHits[$offset-1])) {
+                        $byDayResults[] = $dayHits[$offset-1];
+                    }
+                } else {
+
+                    // if it was negative we count from the end of the array
+                    $byDayResults[] = $dayHits[count($dayHits) + $offset];
+                }
+            } else {
+                // There was no counter (first, second, last wednesdays), so we
+                // just need to add the all to the list).
+                $byDayResults = array_merge($byDayResults, $dayHits);
+
+            }
+
+        }
+
+        $byMonthDayResults = array();
+        if ($this->byMonthDay) foreach($this->byMonthDay as $monthDay) {
+
+            // Removing values that are out of range for this month
+            if ($monthDay > $startDate->format('t') ||
+                $monthDay < 0-$startDate->format('t')) {
+                    continue;
+            }
+            if ($monthDay>0) {
+                $byMonthDayResults[] = $monthDay;
+            } else {
+                // Negative values
+                $byMonthDayResults[] = $startDate->format('t') + 1 + $monthDay;
+            }
+        }
+
+        // If there was just byDay or just byMonthDay, they just specify our
+        // (almost) final list. If both were provided, then byDay limits the
+        // list.
+        if ($this->byMonthDay && $this->byDay) {
+            $result = array_intersect($byMonthDayResults, $byDayResults);
+        } elseif ($this->byMonthDay) {
+            $result = $byMonthDayResults;
+        } else {
+            $result = $byDayResults;
+        }
+        $result = array_unique($result);
+        sort($result, SORT_NUMERIC);
+
+        // The last thing that needs checking is the BYSETPOS. If it's set, it
+        // means only certain items in the set survive the filter.
+        if (!$this->bySetPos) {
+            return $result;
+        }
+
+        $filteredResult = array();
+        foreach($this->bySetPos as $setPos) {
+
+            if ($setPos<0) {
+                $setPos = count($result)-($setPos+1);
+            }
+            if (isset($result[$setPos-1])) {
+                $filteredResult[] = $result[$setPos-1];
+            }
+        }
+
+        sort($filteredResult, SORT_NUMERIC);
+        return $filteredResult;
+
+    }
+
+    protected function getHours()
+    {
+        $recurrenceHours = array();
+        foreach($this->byHour as $byHour) {
+            $recurrenceHours[] = $byHour;
+        }
+
+        return $recurrenceHours;
+    }
+
+    protected function getDays()
+    {
+        $recurrenceDays = array();
+        foreach($this->byDay as $byDay) {
+
+            // The day may be preceeded with a positive (+n) or
+            // negative (-n) integer. However, this does not make
+            // sense in 'weekly' so we ignore it here.
+            $recurrenceDays[] = $this->dayMap[substr($byDay,-2)];
+
+        }
+
+        return $recurrenceDays;
+    }
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/ICalendar.php b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/ICalendar.php
new file mode 100644
index 000000000..657cfb810
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/ICalendar.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace Sabre\VObject\Splitter;
+
+use Sabre\VObject;
+
+/**
+ * Splitter
+ *
+ * This class is responsible for splitting up iCalendar objects.
+ *
+ * This class expects a single VCALENDAR object with one or more
+ * calendar-objects inside. Objects with identical UID's will be combined into
+ * a single object.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Dominik Tobschall
+ * @author Armin Hackmann
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class ICalendar implements SplitterInterface {
+
+    /**
+     * Timezones
+     *
+     * @var array
+     */
+    protected $vtimezones = array();
+
+    /**
+     * iCalendar objects
+     *
+     * @var array
+     */
+    protected $objects = array();
+
+    /**
+     * Constructor
+     *
+     * The splitter should receive an readable file stream as it's input.
+     *
+     * @param resource $input
+     */
+    public function __construct($input) {
+
+        $data = VObject\Reader::read(stream_get_contents($input));
+        $vtimezones = array();
+        $components = array();
+
+        foreach($data->children as $component) {
+            if (!$component instanceof VObject\Component) {
+                continue;
+            }
+
+            // Get all timezones
+            if ($component->name === 'VTIMEZONE') {
+                $this->vtimezones[(string)$component->TZID] = $component;
+                continue;
+            }
+
+            // Get component UID for recurring Events search
+            if($component->UID) {
+                $uid = (string)$component->UID;
+            } else {
+                // Generating a random UID
+                $uid = sha1(microtime()) . '-vobjectimport';
+            }
+
+            // Take care of recurring events
+            if (!array_key_exists($uid, $this->objects)) {
+                $this->objects[$uid] = VObject\Component::create('VCALENDAR');
+            }
+
+            $this->objects[$uid]->add(clone $component);
+        }
+
+    }
+
+    /**
+     * Every time getNext() is called, a new object will be parsed, until we
+     * hit the end of the stream.
+     *
+     * When the end is reached, null will be returned.
+     *
+     * @return Sabre\VObject\Component|null
+     */
+    public function getNext() {
+
+        if($object=array_shift($this->objects)) {
+
+            // create our baseobject
+            $object->version = '2.0';
+            $object->prodid = '-//Sabre//Sabre VObject ' . VObject\Version::VERSION . '//EN';
+            $object->calscale = 'GREGORIAN';
+
+            // add vtimezone information to obj (if we have it)
+            foreach ($this->vtimezones as $vtimezone) {
+                $object->add($vtimezone);
+            }
+
+            return $object;
+
+        } else {
+
+            return null;
+
+        }
+
+   }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/SplitterInterface.php b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/SplitterInterface.php
new file mode 100644
index 000000000..c0126883a
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/SplitterInterface.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Sabre\VObject\Splitter;
+
+/**
+ * VObject splitter
+ *
+ * The splitter is responsible for reading a large vCard or iCalendar object,
+ * and splitting it into multiple objects.
+ *
+ * This is for example for Card and CalDAV, which require every event and vcard
+ * to exist in their own objects, instead of one large one.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Dominik Tobschall
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+interface SplitterInterface {
+
+    /**
+     * Constructor
+     *
+     * The splitter should receive an readable file stream as it's input.
+     *
+     * @param resource $input
+     */
+    function __construct($input);
+
+    /**
+     * Every time getNext() is called, a new object will be parsed, until we
+     * hit the end of the stream.
+     *
+     * When the end is reached, null will be returned.
+     *
+     * @return Sabre\VObject\Component|null
+     */
+    function getNext();
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/VCard.php b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/VCard.php
new file mode 100644
index 000000000..7a8718c00
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Splitter/VCard.php
@@ -0,0 +1,76 @@
+<?php
+
+namespace Sabre\VObject\Splitter;
+
+use Sabre\VObject;
+
+/**
+ * Splitter
+ *
+ * This class is responsible for splitting up VCard objects.
+ *
+ * It is assumed that the input stream contains 1 or more VCARD objects. This
+ * class checks for BEGIN:VCARD and END:VCARD and parses each encountered
+ * component individually.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Dominik Tobschall
+ * @author Armin Hackmann
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class VCard implements SplitterInterface {
+
+    /**
+     * File handle
+     *
+     * @var resource
+     */
+    protected $input;
+
+    /**
+     * Constructor
+     *
+     * The splitter should receive an readable file stream as it's input.
+     *
+     * @param resource $input
+     */
+    public function __construct($input) {
+
+        $this->input = $input;
+
+    }
+
+    /**
+     * Every time getNext() is called, a new object will be parsed, until we
+     * hit the end of the stream.
+     *
+     * When the end is reached, null will be returned.
+     *
+     * @return Sabre\VObject\Component|null
+     */
+    public function getNext() {
+
+        $vcard = '';
+
+        do {
+
+            if (feof($this->input)) {
+                return false;
+            }
+
+            $line = fgets($this->input);
+            $vcard .= $line;
+
+        } while(strtoupper(substr($line,0,4))!=="END:");
+
+        $object = VObject\Reader::read($vcard);
+
+        if($object->name !== 'VCARD') {
+            throw new \InvalidArgumentException("Thats no vCard!", 1);
+        }
+
+        return $object;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/StringUtil.php b/vendor/sabre/vobject/lib/Sabre/VObject/StringUtil.php
new file mode 100644
index 000000000..ea88e1e86
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/StringUtil.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * Useful utilities for working with various strings.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class StringUtil {
+
+    /**
+     * Returns true or false depending on if a string is valid UTF-8
+     *
+     * @param string $str
+     * @return bool
+     */
+    static function isUTF8($str) {
+
+        // First check.. mb_check_encoding
+        if (!mb_check_encoding($str, 'UTF-8')) {
+            return false;
+        }
+
+        // Control characters
+        if (preg_match('%(?:[\x00-\x08\x0B-\x0C\x0E\x0F])%', $str)) {
+            return false;
+        }
+
+        return true;
+
+    }
+
+    /**
+     * This method tries its best to convert the input string to UTF-8.
+     *
+     * Currently only ISO-5991-1 input and UTF-8 input is supported, but this
+     * may be expanded upon if we receive other examples.
+     *
+     * @param string $str
+     * @return string
+     */
+    static function convertToUTF8($str) {
+
+        $encoding = mb_detect_encoding($str , array('UTF-8','ISO-8859-1'), true);
+
+        if ($encoding === 'ISO-8859-1') {
+            $newStr = utf8_encode($str);
+        } else {
+            $newStr = $str;
+        }
+
+        // Removing any control characters
+        return (preg_replace('%(?:[\x00-\x08\x0B-\x0C\x0E\x0F])%', '', $newStr));
+
+    }
+
+}
+
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/TimeZoneUtil.php b/vendor/sabre/vobject/lib/Sabre/VObject/TimeZoneUtil.php
new file mode 100644
index 000000000..6f5b69f3f
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/TimeZoneUtil.php
@@ -0,0 +1,482 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * Time zone name translation
+ *
+ * This file translates well-known time zone names into "Olson database" time zone names.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Frank Edelhaeuser (fedel@users.sourceforge.net)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class TimeZoneUtil {
+
+    public static $map = array(
+
+        // from http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/zone_tzid.html
+        // snapshot taken on 2012/01/16
+
+        // windows
+        'AUS Central Standard Time'=>'Australia/Darwin',
+        'AUS Eastern Standard Time'=>'Australia/Sydney',
+        'Afghanistan Standard Time'=>'Asia/Kabul',
+        'Alaskan Standard Time'=>'America/Anchorage',
+        'Arab Standard Time'=>'Asia/Riyadh',
+        'Arabian Standard Time'=>'Asia/Dubai',
+        'Arabic Standard Time'=>'Asia/Baghdad',
+        'Argentina Standard Time'=>'America/Buenos_Aires',
+        'Armenian Standard Time'=>'Asia/Yerevan',
+        'Atlantic Standard Time'=>'America/Halifax',
+        'Azerbaijan Standard Time'=>'Asia/Baku',
+        'Azores Standard Time'=>'Atlantic/Azores',
+        'Bangladesh Standard Time'=>'Asia/Dhaka',
+        'Canada Central Standard Time'=>'America/Regina',
+        'Cape Verde Standard Time'=>'Atlantic/Cape_Verde',
+        'Caucasus Standard Time'=>'Asia/Yerevan',
+        'Cen. Australia Standard Time'=>'Australia/Adelaide',
+        'Central America Standard Time'=>'America/Guatemala',
+        'Central Asia Standard Time'=>'Asia/Almaty',
+        'Central Brazilian Standard Time'=>'America/Cuiaba',
+        'Central Europe Standard Time'=>'Europe/Budapest',
+        'Central European Standard Time'=>'Europe/Warsaw',
+        'Central Pacific Standard Time'=>'Pacific/Guadalcanal',
+        'Central Standard Time'=>'America/Chicago',
+        'Central Standard Time (Mexico)'=>'America/Mexico_City',
+        'China Standard Time'=>'Asia/Shanghai',
+        'Dateline Standard Time'=>'Etc/GMT+12',
+        'E. Africa Standard Time'=>'Africa/Nairobi',
+        'E. Australia Standard Time'=>'Australia/Brisbane',
+        'E. Europe Standard Time'=>'Europe/Minsk',
+        'E. South America Standard Time'=>'America/Sao_Paulo',
+        'Eastern Standard Time'=>'America/New_York',
+        'Egypt Standard Time'=>'Africa/Cairo',
+        'Ekaterinburg Standard Time'=>'Asia/Yekaterinburg',
+        'FLE Standard Time'=>'Europe/Kiev',
+        'Fiji Standard Time'=>'Pacific/Fiji',
+        'GMT Standard Time'=>'Europe/London',
+        'GTB Standard Time'=>'Europe/Istanbul',
+        'Georgian Standard Time'=>'Asia/Tbilisi',
+        'Greenland Standard Time'=>'America/Godthab',
+        'Greenwich Standard Time'=>'Atlantic/Reykjavik',
+        'Hawaiian Standard Time'=>'Pacific/Honolulu',
+        'India Standard Time'=>'Asia/Calcutta',
+        'Iran Standard Time'=>'Asia/Tehran',
+        'Israel Standard Time'=>'Asia/Jerusalem',
+        'Jordan Standard Time'=>'Asia/Amman',
+        'Kamchatka Standard Time'=>'Asia/Kamchatka',
+        'Korea Standard Time'=>'Asia/Seoul',
+        'Magadan Standard Time'=>'Asia/Magadan',
+        'Mauritius Standard Time'=>'Indian/Mauritius',
+        'Mexico Standard Time'=>'America/Mexico_City',
+        'Mexico Standard Time 2'=>'America/Chihuahua',
+        'Mid-Atlantic Standard Time'=>'Etc/GMT-2',
+        'Middle East Standard Time'=>'Asia/Beirut',
+        'Montevideo Standard Time'=>'America/Montevideo',
+        'Morocco Standard Time'=>'Africa/Casablanca',
+        'Mountain Standard Time'=>'America/Denver',
+        'Mountain Standard Time (Mexico)'=>'America/Chihuahua',
+        'Myanmar Standard Time'=>'Asia/Rangoon',
+        'N. Central Asia Standard Time'=>'Asia/Novosibirsk',
+        'Namibia Standard Time'=>'Africa/Windhoek',
+        'Nepal Standard Time'=>'Asia/Katmandu',
+        'New Zealand Standard Time'=>'Pacific/Auckland',
+        'Newfoundland Standard Time'=>'America/St_Johns',
+        'North Asia East Standard Time'=>'Asia/Irkutsk',
+        'North Asia Standard Time'=>'Asia/Krasnoyarsk',
+        'Pacific SA Standard Time'=>'America/Santiago',
+        'Pacific Standard Time'=>'America/Los_Angeles',
+        'Pacific Standard Time (Mexico)'=>'America/Santa_Isabel',
+        'Pakistan Standard Time'=>'Asia/Karachi',
+        'Paraguay Standard Time'=>'America/Asuncion',
+        'Romance Standard Time'=>'Europe/Paris',
+        'Russian Standard Time'=>'Europe/Moscow',
+        'SA Eastern Standard Time'=>'America/Cayenne',
+        'SA Pacific Standard Time'=>'America/Bogota',
+        'SA Western Standard Time'=>'America/La_Paz',
+        'SE Asia Standard Time'=>'Asia/Bangkok',
+        'Samoa Standard Time'=>'Pacific/Apia',
+        'Singapore Standard Time'=>'Asia/Singapore',
+        'South Africa Standard Time'=>'Africa/Johannesburg',
+        'Sri Lanka Standard Time'=>'Asia/Colombo',
+        'Syria Standard Time'=>'Asia/Damascus',
+        'Taipei Standard Time'=>'Asia/Taipei',
+        'Tasmania Standard Time'=>'Australia/Hobart',
+        'Tokyo Standard Time'=>'Asia/Tokyo',
+        'Tonga Standard Time'=>'Pacific/Tongatapu',
+        'US Eastern Standard Time'=>'America/Indianapolis',
+        'US Mountain Standard Time'=>'America/Phoenix',
+        'UTC+12'=>'Etc/GMT-12',
+        'UTC-02'=>'Etc/GMT+2',
+        'UTC-11'=>'Etc/GMT+11',
+        'Ulaanbaatar Standard Time'=>'Asia/Ulaanbaatar',
+        'Venezuela Standard Time'=>'America/Caracas',
+        'Vladivostok Standard Time'=>'Asia/Vladivostok',
+        'W. Australia Standard Time'=>'Australia/Perth',
+        'W. Central Africa Standard Time'=>'Africa/Lagos',
+        'W. Europe Standard Time'=>'Europe/Berlin',
+        'West Asia Standard Time'=>'Asia/Tashkent',
+        'West Pacific Standard Time'=>'Pacific/Port_Moresby',
+        'Yakutsk Standard Time'=>'Asia/Yakutsk',
+
+        // Microsoft exchange timezones
+        // Source:
+        // http://msdn.microsoft.com/en-us/library/ms988620%28v=exchg.65%29.aspx
+        //
+        // Correct timezones deduced with help from:
+        // http://en.wikipedia.org/wiki/List_of_tz_database_time_zones
+        'Universal Coordinated Time' => 'UTC',
+        'Casablanca, Monrovia' => 'Africa/Casablanca',
+        'Greenwich Mean Time: Dublin, Edinburgh, Lisbon, London' => 'Europe/Lisbon',
+        'Greenwich Mean Time; Dublin, Edinburgh, London' =>  'Europe/London',
+        'Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna' => 'Europe/Berlin',
+        'Belgrade, Pozsony, Budapest, Ljubljana, Prague' => 'Europe/Prague',
+        'Brussels, Copenhagen, Madrid, Paris' => 'Europe/Paris',
+        'Paris, Madrid, Brussels, Copenhagen' => 'Europe/Paris',
+        'Prague, Central Europe' => 'Europe/Prague',
+        'Sarajevo, Skopje, Sofija, Vilnius, Warsaw, Zagreb' => 'Europe/Sarajevo',
+        'West Central Africa' => 'Africa/Luanda', // This was a best guess
+        'Athens, Istanbul, Minsk' => 'Europe/Athens',
+        'Bucharest' => 'Europe/Bucharest',
+        'Cairo' => 'Africa/Cairo',
+        'Harare, Pretoria' => 'Africa/Harare',
+        'Helsinki, Riga, Tallinn' => 'Europe/Helsinki',
+        'Israel, Jerusalem Standard Time' => 'Asia/Jerusalem',
+        'Baghdad' => 'Asia/Baghdad',
+        'Arab, Kuwait, Riyadh' => 'Asia/Kuwait',
+        'Moscow, St. Petersburg, Volgograd' => 'Europe/Moscow',
+        'East Africa, Nairobi' => 'Africa/Nairobi',
+        'Tehran' => 'Asia/Tehran',
+        'Abu Dhabi, Muscat' => 'Asia/Muscat', // Best guess
+        'Baku, Tbilisi, Yerevan' => 'Asia/Baku',
+        'Kabul' => 'Asia/Kabul',
+        'Ekaterinburg' => 'Asia/Yekaterinburg',
+        'Islamabad, Karachi, Tashkent' => 'Asia/Karachi',
+        'Kolkata, Chennai, Mumbai, New Delhi, India Standard Time' => 'Asia/Calcutta',
+        'Kathmandu, Nepal' => 'Asia/Kathmandu',
+        'Almaty, Novosibirsk, North Central Asia' => 'Asia/Almaty',
+        'Astana, Dhaka' => 'Asia/Dhaka',
+        'Sri Jayawardenepura, Sri Lanka' => 'Asia/Colombo',
+        'Rangoon' => 'Asia/Rangoon',
+        'Bangkok, Hanoi, Jakarta' => 'Asia/Bangkok',
+        'Krasnoyarsk' => 'Asia/Krasnoyarsk',
+        'Beijing, Chongqing, Hong Kong SAR, Urumqi' => 'Asia/Shanghai',
+        'Irkutsk, Ulaan Bataar' => 'Asia/Irkutsk',
+        'Kuala Lumpur, Singapore' => 'Asia/Singapore',
+        'Perth, Western Australia' => 'Australia/Perth',
+        'Taipei' => 'Asia/Taipei',
+        'Osaka, Sapporo, Tokyo' => 'Asia/Tokyo',
+        'Seoul, Korea Standard time' => 'Asia/Seoul',
+        'Yakutsk' => 'Asia/Yakutsk',
+        'Adelaide, Central Australia' => 'Australia/Adelaide',
+        'Darwin' => 'Australia/Darwin',
+        'Brisbane, East Australia' => 'Australia/Brisbane',
+        'Canberra, Melbourne, Sydney, Hobart (year 2000 only)' => 'Australia/Sydney',
+        'Guam, Port Moresby' => 'Pacific/Guam',
+        'Hobart, Tasmania' => 'Australia/Hobart',
+        'Vladivostok' => 'Asia/Vladivostok',
+        'Magadan, Solomon Is., New Caledonia' => 'Asia/Magadan',
+        'Auckland, Wellington' => 'Pacific/Auckland',
+        'Fiji Islands, Kamchatka, Marshall Is.' => 'Pacific/Fiji',
+        'Nuku\'alofa, Tonga' => 'Pacific/Tongatapu',
+        'Azores' => 'Atlantic/Azores',
+        'Cape Verde Is.' => 'Atlantic/Cape_Verde',
+        'Mid-Atlantic' => 'America/Noronha',
+        'Brasilia' => 'America/Sao_Paulo', // Best guess
+        'Buenos Aires' => 'America/Argentina/Buenos_Aires',
+        'Greenland' => 'America/Godthab',
+        'Newfoundland' => 'America/St_Johns',
+        'Atlantic Time (Canada)' => 'America/Halifax',
+        'Caracas, La Paz' => 'America/Caracas',
+        'Santiago' => 'America/Santiago',
+        'Bogota, Lima, Quito' => 'America/Bogota',
+        'Eastern Time (US & Canada)' => 'America/New_York',
+        'Indiana (East)' => 'America/Indiana/Indianapolis',
+        'Central America' => 'America/Guatemala',
+        'Central Time (US & Canada)' => 'America/Chicago',
+        'Mexico City, Tegucigalpa' => 'America/Mexico_City',
+        'Saskatchewan' => 'America/Edmonton',
+        'Arizona' => 'America/Phoenix',
+        'Mountain Time (US & Canada)' => 'America/Denver', // Best guess
+        'Pacific Time (US & Canada); Tijuana' => 'America/Los_Angeles', // Best guess
+        'Alaska' => 'America/Anchorage',
+        'Hawaii' => 'Pacific/Honolulu',
+        'Midway Island, Samoa' => 'Pacific/Midway',
+        'Eniwetok, Kwajalein, Dateline Time' => 'Pacific/Kwajalein',
+
+        // The following list are timezone names that could be generated by
+        // Lotus / Domino
+        'Dateline'               => 'Etc/GMT-12',
+        'Samoa'                  => 'Pacific/Apia',
+        'Hawaiian'               => 'Pacific/Honolulu',
+        'Alaskan'                => 'America/Anchorage',
+        'Pacific'                => 'America/Los_Angeles',
+        'Pacific Standard Time'  => 'America/Los_Angeles',
+        'Mexico Standard Time 2' => 'America/Chihuahua',
+        'Mountain'               => 'America/Denver',
+        'Mountain Standard Time' => 'America/Chihuahua',
+        'US Mountain'            => 'America/Phoenix',
+        'Canada Central'         => 'America/Edmonton',
+        'Central America'        => 'America/Guatemala',
+        'Central'                => 'America/Chicago',
+        'Central Standard Time'  => 'America/Mexico_City',
+        'Mexico'                 => 'America/Mexico_City',
+        'Eastern'                => 'America/New_York',
+        'SA Pacific'             => 'America/Bogota',
+        'US Eastern'             => 'America/Indiana/Indianapolis',
+        'Venezuela'              => 'America/Caracas',
+        'Atlantic'               => 'America/Halifax',
+        'Central Brazilian'      => 'America/Manaus',
+        'Pacific SA'             => 'America/Santiago',
+        'SA Western'             => 'America/La_Paz',
+        'Newfoundland'           => 'America/St_Johns',
+        'Argentina'              => 'America/Argentina/Buenos_Aires',
+        'E. South America'       => 'America/Belem',
+        'Greenland'              => 'America/Godthab',
+        'Montevideo'             => 'America/Montevideo',
+        'SA Eastern'             => 'America/Belem',
+        'Mid-Atlantic'           => 'Etc/GMT-2',
+        'Azores'                 => 'Atlantic/Azores',
+        'Cape Verde'             => 'Atlantic/Cape_Verde',
+        'Greenwich'              => 'Atlantic/Reykjavik', // No I'm serious.. Greenwich is not GMT.
+        'Morocco'                => 'Africa/Casablanca',
+        'Central Europe'         => 'Europe/Prague',
+        'Central European'       => 'Europe/Sarajevo',
+        'Romance'                => 'Europe/Paris',
+        'W. Central Africa'      => 'Africa/Lagos', // Best guess
+        'W. Europe'              => 'Europe/Amsterdam',
+        'E. Europe'              => 'Europe/Minsk',
+        'Egypt'                  => 'Africa/Cairo',
+        'FLE'                    => 'Europe/Helsinki',
+        'GTB'                    => 'Europe/Athens',
+        'Israel'                 => 'Asia/Jerusalem',
+        'Jordan'                 => 'Asia/Amman',
+        'Middle East'            => 'Asia/Beirut',
+        'Namibia'                => 'Africa/Windhoek',
+        'South Africa'           => 'Africa/Harare',
+        'Arab'                   => 'Asia/Kuwait',
+        'Arabic'                 => 'Asia/Baghdad',
+        'E. Africa'              => 'Africa/Nairobi',
+        'Georgian'               => 'Asia/Tbilisi',
+        'Russian'                => 'Europe/Moscow',
+        'Iran'                   => 'Asia/Tehran',
+        'Arabian'                => 'Asia/Muscat',
+        'Armenian'               => 'Asia/Yerevan',
+        'Azerbijan'              => 'Asia/Baku',
+        'Caucasus'               => 'Asia/Yerevan',
+        'Mauritius'              => 'Indian/Mauritius',
+        'Afghanistan'            => 'Asia/Kabul',
+        'Ekaterinburg'           => 'Asia/Yekaterinburg',
+        'Pakistan'               => 'Asia/Karachi',
+        'West Asia'              => 'Asia/Tashkent',
+        'India'                  => 'Asia/Calcutta',
+        'Sri Lanka'              => 'Asia/Colombo',
+        'Nepal'                  => 'Asia/Kathmandu',
+        'Central Asia'           => 'Asia/Dhaka',
+        'N. Central Asia'        => 'Asia/Almaty',
+        'Myanmar'                => 'Asia/Rangoon',
+        'North Asia'             => 'Asia/Krasnoyarsk',
+        'SE Asia'                => 'Asia/Bangkok',
+        'China'                  => 'Asia/Shanghai',
+        'North Asia East'        => 'Asia/Irkutsk',
+        'Singapore'              => 'Asia/Singapore',
+        'Taipei'                 => 'Asia/Taipei',
+        'W. Australia'           => 'Australia/Perth',
+        'Korea'                  => 'Asia/Seoul',
+        'Tokyo'                  => 'Asia/Tokyo',
+        'Yakutsk'                => 'Asia/Yakutsk',
+        'AUS Central'            => 'Australia/Darwin',
+        'Cen. Australia'         => 'Australia/Adelaide',
+        'AUS Eastern'            => 'Australia/Sydney',
+        'E. Australia'           => 'Australia/Brisbane',
+        'Tasmania'               => 'Australia/Hobart',
+        'Vladivostok'            => 'Asia/Vladivostok',
+        'West Pacific'           => 'Pacific/Guam',
+        'Central Pacific'        => 'Asia/Magadan',
+        'Fiji'                   => 'Pacific/Fiji',
+        'New Zealand'            => 'Pacific/Auckland',
+        'Tonga'                  => 'Pacific/Tongatapu',
+    );
+
+    /**
+     * List of microsoft exchange timezone ids.
+     *
+     * Source: http://msdn.microsoft.com/en-us/library/aa563018(loband).aspx
+     */
+    public static $microsoftExchangeMap = array(
+        0  => 'UTC',
+        31 => 'Africa/Casablanca',
+
+        // Insanely, id #2 is used for both Europe/Lisbon, and Europe/Sarajevo.
+        // I'm not even kidding.. We handle this special case in the
+        // getTimeZone method.
+        2  => 'Europe/Lisbon',
+        1  => 'Europe/London',
+        4  => 'Europe/Berlin',
+        6  => 'Europe/Prague',
+        3  => 'Europe/Paris',
+        69 => 'Africa/Luanda', // This was a best guess
+        7  => 'Europe/Athens',
+        5  => 'Europe/Bucharest',
+        49 => 'Africa/Cairo',
+        50 => 'Africa/Harare',
+        59 => 'Europe/Helsinki',
+        27 => 'Asia/Jerusalem',
+        26 => 'Asia/Baghdad',
+        74 => 'Asia/Kuwait',
+        51 => 'Europe/Moscow',
+        56 => 'Africa/Nairobi',
+        25 => 'Asia/Tehran',
+        24 => 'Asia/Muscat', // Best guess
+        54 => 'Asia/Baku',
+        48 => 'Asia/Kabul',
+        58 => 'Asia/Yekaterinburg',
+        47 => 'Asia/Karachi',
+        23 => 'Asia/Calcutta',
+        62 => 'Asia/Kathmandu',
+        46 => 'Asia/Almaty',
+        71 => 'Asia/Dhaka',
+        66 => 'Asia/Colombo',
+        61 => 'Asia/Rangoon',
+        22 => 'Asia/Bangkok',
+        64 => 'Asia/Krasnoyarsk',
+        45 => 'Asia/Shanghai',
+        63 => 'Asia/Irkutsk',
+        21 => 'Asia/Singapore',
+        73 => 'Australia/Perth',
+        75 => 'Asia/Taipei',
+        20 => 'Asia/Tokyo',
+        72 => 'Asia/Seoul',
+        70 => 'Asia/Yakutsk',
+        19 => 'Australia/Adelaide',
+        44 => 'Australia/Darwin',
+        18 => 'Australia/Brisbane',
+        76 => 'Australia/Sydney',
+        43 => 'Pacific/Guam',
+        42 => 'Australia/Hobart',
+        68 => 'Asia/Vladivostok',
+        41 => 'Asia/Magadan',
+        17 => 'Pacific/Auckland',
+        40 => 'Pacific/Fiji',
+        67 => 'Pacific/Tongatapu',
+        29 => 'Atlantic/Azores',
+        53 => 'Atlantic/Cape_Verde',
+        30 => 'America/Noronha',
+         8 => 'America/Sao_Paulo', // Best guess
+        32 => 'America/Argentina/Buenos_Aires',
+        60 => 'America/Godthab',
+        28 => 'America/St_Johns',
+         9 => 'America/Halifax',
+        33 => 'America/Caracas',
+        65 => 'America/Santiago',
+        35 => 'America/Bogota',
+        10 => 'America/New_York',
+        34 => 'America/Indiana/Indianapolis',
+        55 => 'America/Guatemala',
+        11 => 'America/Chicago',
+        37 => 'America/Mexico_City',
+        36 => 'America/Edmonton',
+        38 => 'America/Phoenix',
+        12 => 'America/Denver', // Best guess
+        13 => 'America/Los_Angeles', // Best guess
+        14 => 'America/Anchorage',
+        15 => 'Pacific/Honolulu',
+        16 => 'Pacific/Midway',
+        39 => 'Pacific/Kwajalein',
+    );
+
+    /**
+     * This method will try to find out the correct timezone for an iCalendar
+     * date-time value.
+     *
+     * You must pass the contents of the TZID parameter, as well as the full
+     * calendar.
+     *
+     * If the lookup fails, this method will return the default PHP timezone
+     * (as configured using date_default_timezone_set, or the date.timezone ini
+     * setting).
+     *
+     * Alternatively, if $failIfUncertain is set to true, it will throw an
+     * exception if we cannot accurately determine the timezone.
+     *
+     * @param string $tzid
+     * @param Sabre\VObject\Component $vcalendar
+     * @return DateTimeZone
+     */
+    static public function getTimeZone($tzid, Component $vcalendar = null, $failIfUncertain = false) {
+
+        // First we will just see if the tzid is a support timezone identifier.
+        try {
+            return new \DateTimeZone($tzid);
+        } catch (\Exception $e) {
+        }
+
+        // Next, we check if the tzid is somewhere in our tzid map.
+        if (isset(self::$map[$tzid])) {
+            return new \DateTimeZone(self::$map[$tzid]);
+        }
+
+        // Maybe the author was hyper-lazy and just included an offset. We
+        // support it, but we aren't happy about it.
+        if (preg_match('/^GMT(\+|-)([0-9]{4})$/', $tzid, $matches)) {
+            return new \DateTimeZone('Etc/GMT' . $matches[1] . ltrim(substr($matches[2],0,2),'0'));
+        }
+
+        if ($vcalendar) {
+
+            // If that didn't work, we will scan VTIMEZONE objects
+            foreach($vcalendar->select('VTIMEZONE') as $vtimezone) {
+
+                if ((string)$vtimezone->TZID === $tzid) {
+
+                    // Some clients add 'X-LIC-LOCATION' with the olson name.
+                    if (isset($vtimezone->{'X-LIC-LOCATION'})) {
+
+                        $lic = (string)$vtimezone->{'X-LIC-LOCATION'};
+
+                        // Libical generators may specify strings like
+                        // "SystemV/EST5EDT". For those we must remove the
+                        // SystemV part.
+                        if (substr($lic,0,8)==='SystemV/') {
+                            $lic = substr($lic,8);
+                        }
+
+                        try {
+                            return new \DateTimeZone($lic);
+                        } catch (\Exception $e) {
+                        }
+
+                    }
+                    // Microsoft may add a magic number, which we also have an
+                    // answer for.
+                    if (isset($vtimezone->{'X-MICROSOFT-CDO-TZID'})) {
+                        $cdoId = (int)$vtimezone->{'X-MICROSOFT-CDO-TZID'}->value;
+
+                        // 2 can mean both Europe/Lisbon and Europe/Sarajevo.
+                        if ($cdoId===2 && strpos((string)$vtimezone->TZID, 'Sarajevo')!==false) {
+                            return new \DateTimeZone('Europe/Sarajevo');
+                        }
+
+                        if (isset(self::$microsoftExchangeMap[$cdoId])) {
+                            return new \DateTimeZone(self::$microsoftExchangeMap[$cdoId]);
+                        }
+                    }
+
+                }
+
+            }
+
+        }
+
+        if ($failIfUncertain) {
+            throw new \InvalidArgumentException('We were unable to determine the correct PHP timezone for tzid: ' . $tzid);
+        }
+
+        // If we got all the way here, we default to UTC.
+        return new \DateTimeZone(date_default_timezone_get());
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/Version.php b/vendor/sabre/vobject/lib/Sabre/VObject/Version.php
new file mode 100644
index 000000000..2a64140f4
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/Version.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * This class contains the version number for the VObject package
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Version {
+
+    /**
+     * Full version number
+     */
+    const VERSION = '2.1.3';
+
+    /**
+     * Stability : alpha, beta, stable
+     */
+    const STABILITY = 'stable';
+
+}
diff --git a/vendor/sabre/vobject/lib/Sabre/VObject/includes.php b/vendor/sabre/vobject/lib/Sabre/VObject/includes.php
new file mode 100644
index 000000000..d15329a6a
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Sabre/VObject/includes.php
@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * Includes file
+ *
+ * This file includes the entire VObject library in one go.
+ * The benefit is that an autoloader is not needed, which is often faster.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+
+// Begin includes
+include __DIR__ . '/DateTimeParser.php';
+include __DIR__ . '/ElementList.php';
+include __DIR__ . '/FreeBusyGenerator.php';
+include __DIR__ . '/Node.php';
+include __DIR__ . '/Parameter.php';
+include __DIR__ . '/ParseException.php';
+include __DIR__ . '/Property.php';
+include __DIR__ . '/Reader.php';
+include __DIR__ . '/RecurrenceIterator.php';
+include __DIR__ . '/Splitter/SplitterInterface.php';
+include __DIR__ . '/StringUtil.php';
+include __DIR__ . '/TimeZoneUtil.php';
+include __DIR__ . '/Version.php';
+include __DIR__ . '/Splitter/VCard.php';
+include __DIR__ . '/Component.php';
+include __DIR__ . '/Document.php';
+include __DIR__ . '/Property/Compound.php';
+include __DIR__ . '/Property/DateTime.php';
+include __DIR__ . '/Property/MultiDateTime.php';
+include __DIR__ . '/Splitter/ICalendar.php';
+include __DIR__ . '/Component/VAlarm.php';
+include __DIR__ . '/Component/VCalendar.php';
+include __DIR__ . '/Component/VEvent.php';
+include __DIR__ . '/Component/VFreeBusy.php';
+include __DIR__ . '/Component/VJournal.php';
+include __DIR__ . '/Component/VTodo.php';
+// End includes