GENERAL ISSUES:
- we need a way for a notification whenever the contents of
  a directory in the database are changed. Maybe we just use
  the standard notification schema and add a generic 
  handling routine (instead of artistaddedtosongdb & Co).
  Maybe we just use the songchanged events, which will
  be parsed by the active view!
  Similarly, playlist should appear in playlist dir when saved

BUGS:
- autoplay=true or autoplay=false for secondary player?
- what happens to mpg123 when pytone crashes
- keep track of problem reported by Tomaz Ficko <tomaz@gmx.net> in 
  _unindexsong_genre's elif clause
  same problem reported by Stuart Pook <Stuart.Pook@infres.enst.fr>

BEFORE RELEASE:

USER WISHLIST:

- more than 2 database
- allow user to turn the secondary player on and off (or alternatively to stop it)
  (requested by Stuart Pook)
- streaming sources
- create subdirs for artist only if there are more than a certain number of songs 

- General:
  o calling of external programs from within python
  o timer interface
  o user authentication and permissions
  o allow up- and download of songs
  o make automatic backups of database
  o database reconstruction

- Performance improvements:
  o move number of decades, genres, playlists (do it like for songs)
  o make length calculation of filtereddecade and filteredgenre smarter

- UI Improvements:
  o improve behaviour on scroll bar mouse clicks
  o scrollbars are sometimes too short
  o list of seldomly played songs
  o make showing of last added list configurable (similarly for rest)
  o visual indicator that PyTone is busy
