TODO

 - Rework internal GcalWindow working

 - Add disable/enable of views
 - Rework GcalViews as grid only (WeekView, MonthView, YearView)
 - Rework GcalViews to implement the new API (remove every "New API" comment)
 - Review all-day checkbox and date/time fields interaction in GcalEditDialog
 - Check width of read-only layer in GcalEditDialog
 - Rethink signals from GcalManager
 - Order events chronologically in views
 - Change ordering of events in all-day views (use a custom ordering)
 - Add different triggers for hiding the sources view.
 - Check for the real need of adding timezone, and check everywhere
 - Connect all dconf options to the program
 - Check the real need of a caching GcalManager

Design stuff

 - What to do when there's no host set in the event.
 - Interactions explained
     - When to show/hide sources view
     - When to show/hide new-event overlay
     - Random stuff I don't remember now

Wish-list

 - Add resize-by-handlers capabilities to GcalEventWidget
