changes:

*) De-singleton-ified PlaylistSplitter and made appropriate changes to pass
   a pointer in the few places needed.

*) Added support for renaming a playlist without renaming the file using
   a comment in the m3u file to save the name.

*) Cleaned up the Tag API and made it an abstract class.  I added concrete
   implementations ID3Tag, OggTag and CachedTag, however only ID3Tag has
   an implementation at the moment.

svn path=/trunk/kdemultimedia/juk/; revision=182511