Hooked signals from date and time entries.
Added comparison and adjustment if the interval.
Removed SimpleDate and SimpleTime structs.
Added _get_end_date for end-date change notification.
Initial support for storing event-data so the EditDialog can
tell which properties has changed.
Changed time entries for GcalTimeEntry objects.
Set ::activates-default property of summary_entry to handle change title
with one keystroke.
Added very initial support to handle obtention of the modified properties
of the edited event. There's still some kind of Model implementation to keep
track of the changes made by the user.
Note: There's still missing one pixel border, I can't find the reason today.
And there's still need to theme better the background of the readonly header.
But the major changes are done.
Erick Pérez Castellanos