Added a setting for a calendar if it is for time off. This lets to create 2 separate buttons for new shifts and time off. Also the shifts in the time off calendars are not counted for the totals results in the schedule view.
Added a check to avoid shift types with duplicated start and end times.
BUG: Timezone was not properly set in the iCal feed.
BUG: Full day shift type title was not shown in the schedule view.