Notification sound-to-vibration conversion toggle

Allows to change the new feature of AOSP 4.2, where all notification are
changed to vibrations on vibrate mode. Instead, allow the old behaviour
to silence sound notifications and to only play vibrations if desired.

Alle credits go to romanbb from AOKP, I just ported it.
Original AOKP-Commit:
https://github.com/AOKP/packages_apps_Settings/commit/e92446576c2dfbe51089287c43c3f799b5cc0057

Change-Id: I267fc4b62ff045f305cf29c1b4f365e91f7cf1db

Conflicts:
	res/values/strings.xml
	src/com/android/settings/SoundSettings.java

Signed-off-by: Chuck Haines <chaines@codemonkeyjava.com>