Combined volume panel only in tablets. On phones show active volume.
Added dummy assets for ring+notification icon.
Deprecated the NOTIFICATION_USES_RING_VOLUME. Now they are always
tied together. Audio manager changes still required to ensure that.
Initialize all feedback sounds to true.
Change-Id: I3ad7890c9be9334eedb5f3b709a4b6995fe24638
42722bfa13