Settings: Broadcast ACTION_DATE_CHANGED

Send ACTION_DATE_CHANGED when user change the format of the date

Change-Id: I89ef0354ae2b0825378a6e8939341c4eccf63e17
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
Check if the Activity is finishing before showDialog()

Check if the Activity is going through its finishing phase before
displaying the Dialog, because Showing dialog once the activity
is no longer in context will cause BadTokenException.

Change-Id: I58940e694f61cd79536abe2df60a0b745a7b806f