Bumped docs
Added PHP 5.5 to travis config
Updated lock file
Added phpunit as a dev dependency
Added exception when trying to retrieve events without provider defined. (FIX #17)
Fixed dev dependencies and removed 'dev' as minimum stability
Adding failing test for non-usual first weekdays (#19)
Fixed usual firstweek day tests (#19)
Merge pull request #19 from yohang/fix-unusual-firstweekday

Fixed `DateInterval` Exception when setting a non-usual first weekday
Fixed unwanted extra week for months starting by their first weekday
Merge pull request #20 from yohang/fix-extra-week

Fixed unwanted extra week for months starting by their first weekday
Added failing test for #22

Warning when iterating over non-initialized event array
Added initialization of event array in Basic provider

Fix #22
added Google calendar event provider
Merge pull request #23 from bertrandquequeville/master

Add google calendar event provider
Updated dependencies
add of several attributes in GoogleCalendarEvent

modification of test values
Merge pull request #24 from bertrandquequeville/master

GoogleCalendarEvent several attributes add