Swap volume buttons when the screen is rotated by 90 or 180 degrees (2/2)

Change-Id: Ie2166a4d50050e7a60933251bfc8cda97c42d419

Conflicts:
	res/values/strings.xml
DisplayRotation: Hide Swap volume buttons option if it's not supported

http://review.cyanogenmod.org/#/c/32219/