DeskClock: implement onDowngrade for alarm DB

Upgrade does a database clear anyway, so might as well implement a
downgrade. This fixes alarm clock FC for those upgrading from cm 10.

Change-Id: I5c85a67b671b38e1185e5aeb2e06983452ac5c65
DeskClock: the first day of the week depends on a locale

Change-Id: I800bcd16a802540c28303e1b48874e2ead33fd22
Make the settings menu accessible on every tab

Change-Id: Ieb7fdf09e4369701868c52a327aca458c01ed49c