playlistcontainer: folder support
Merge pull request #1 from LinusU/patch-1

playlistcontainer: folder support
Merge pull request #3 from LinusU/patch-2

album cover retrieving
albumcover: more functions
0.2.2
credit swissmany and LinusU
slightly refactors tests for playlists
Merge pull request #4 from LinusU/patch-3

starred playlist support
merge the latest changes from upstream