Forward port Volume panel style and Linked volumes

Original author ptunstal

Change-Id: I4359550fabd110ced6359d2bdcd321561b08fae0

Conflicts:
	core/java/android/view/VolumePanel.java

 Author:    DvTonder <david.vantonder@gmail.com>
 On branch jb422
 Changes to be committed:
	modified:   core/java/android/view/VolumePanel.java
	modified:   media/java/android/media/AudioService.java