Added playlist persistence functions.
Merge branch 'master' of https://github.com/HSLUStefanBachmann/PAWI_AndroidPlaylist

Conflicts:
	AndroidPlaylisten/src/ch/hslu/h1301/pawi/androidplaylisten/FragmentPlaybackEditHandlePlaylist.java
	AndroidPlaylisten/src/ch/hslu/h1301/pawi/androidplaylisten/FragmentPlaybackPlaylist.java