[2/2] settings: volume tweaks

Setting to disable volume adjust sounds (VOLUME_ADJUST_SOUNDS_ENABLED)
This is so annoying :)

Enhanced dialog to add checkbox for unlinking ringer and
notification volume (VOLUME_LINK_NOTIFICATION)

Change-Id: I823d7a31caec6c76127a796f14804634fea80bbe
Merge "[2/2] settings: volume tweaks" into android-4.3