Feature: Bedtime calculator

Adds a bedtime calculator to each alarm. The calculator works by
counting backwards in sleep cyles (90 minutes), then calculating the
times you'd need to go to sleep in order to wake up in between them. It
can help you wake up feeling less groggy. The calculator displays four
suggested sleep times ranging from 4.5-9 hours of sleep.

Change-Id: I7ad932da7955d8f058392562ffc85c9af0f5206f
DeskClock: User-defined world cities

Support for add user-defined cities to the world clock

Patchset 2: Added GPS query
Patchset 3: Added GPS drawables
            Call requestGpsLocation in background
Patchset 4: Added timezone resolution through Google Api
            Added Marco suggestions
            Rebased
Patchset 5: Remove trailing whitespaces
Patchset 6: Moved cm strings to the end of the file
            Rebased
Patchset 7: Export DbCityProvider. Enforce write permission to DeskClock only
Patchset 8: Fix FC when there is no default timezone
            Add content description to GPS button
            Don't create a new city record of city name + city tz already exists
Patchset 9: Rebased
Patchset 10: Rebased (Moved string to cm_string)

Change-Id: Ibb6febc674ca536728367588437fbdacaa437ff3
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>