[2/2] Settings: opens music app when headset is plugged and more ...

-[2/2] Settings: Headset plug: Disable if music is active by @UtkarshGupta
-[1/2] Settings: Headset: headset actions improvement by Juan Ezquerro LLanes
-Added AppSelectListPreference by Pierre Gros

Change-Id: Ibb87466cc7cf7ce127a712b161a9476ef35dbe6e

Conflicts:

	res/values/mahdi_attrs.xml
	res/values/mahdi_strings.xml
	res/values/slim_arrays.xml
	res/xml/mahdi_sound_settings.xml
	src/com/android/settings/mahdi/SoundSettings.java