MediaFile: support more media types

Change-Id: Ib3109c5ebc762b97e45bd0bb5fa82ad77b0e6822
UserTile: Fix displaying user information for multi-user devices

In commit 89ab0eb097322ac8eec40159b888dfb03b9413e9, we improved
the handling of single user devices but appear to have also
entirely deleted the name / avatar for multi-user devices.

This commit restores the deleted code for multi-user devices.

This fixes CYAN-4023.

Change-Id: I69fe1504da2b32cd5bf0fdc87f8f78c960e9c77f
audio: no notification sound when adjusting volume bar twice.

Notification sound won't take effect when the previous track hasn't
finished.
Need explicitly stop the previous ongoing track to alow the current one.

Change-Id: Ib344a8b14ecc47a5c8fdd9c11ae48a3541ea9a55
CRs-Fixed: 652236