skipping to next album breaks indexing

[noah]

Traceback (most recent call last):
  File "bin/riddim", line 65, in <module>
    main()
  File "bin/riddim", line 35, in main
    elif args.next_album            : print playlist.next_album()
  File "riddim/lib/playlist.py", line 389, in next_album
    album_next = self.song().album
  File "riddim/lib/playlist.py", line 383, in song
    return self.data[u'playlist'][self.data[u'index']]
KeyError: 83

Need tests.