Quiet Hours: allow disabling of system sounds (2 of 2)

* this includes touch and lockscreen sounds

Change-Id: Ib703beefbadcae225e892936e1fc9f87415703af
Merge "Quiet Hours: allow disabling of system sounds (2 of 2)" into cm-10.2
Merge remote-tracking branch 'upstream/cm-10.2' into cm-10.2