DeskClock: Support double-digit hours for timers

Change-Id: I8aa4960c03d710ca7889c8d91701ca5b5376c9ef
DeskClock: Add feature to play random song as an alarm.

Change-Id: I38c346beb0746fcebd224e9641e2d397183ba9a2
DeskClock: Fix NullPointerException in AlarmClockFragment

RingtoneManager.getRingtone could return null so add a check for that

Change-Id: Ic3ec042e7c3fe02eee6388a469f19624d90fdddd