Invalidate cache

Now invalidates cache when plugin settings are changed.
Fixes for all day events

Various fixes, especially for all day events
Merge remote-tracking branch 'origin/full' into eot

Conflicts:
	languages/en.php
	models/model.php
	start.php
	views/default/event_calendar/datetime_edit.php
	views/default/event_calendar/full_calendar_view.php
	views/default/event_calendar/repeat_form_element.php
	views/default/forms/event_calendar/edit.php
	views/default/js/event_calendar/event_calendar.php
locale changes to full_calendar_view.php