Android 5.0: extract new Switch style attributes

Switch_showText specifies whether the on/off text is shown in the
thumb and Switch_splitTrack specifies whether the track is clipped
underneath the thumb.

Change-Id: I03fc6b799fe714e7b6e604328901c8c5a418ca6e
Reviewed-by: BogDan Vatra <bogdan@kde.org>