- support for "total number of discs"
   * setting to enable / disable writing the total number of discs
   * total number of discs is written to MP3, MP2, FLAC, Ogg Vorbis,
Monkey's Audio and WavPack
- autonumbering of "disc" (using folders to determine to which disc a
   file belongs; equivalent to "track autonumbering")
- some more scanner masks (which are chosen arbitrarily :))
   %x - total number of discs
   %k - file index
   %m - total number of files in list
- scan processor "fill field" which allows to fill a fill using the
   the tag data (utilizing the mask processing)
- fixed a bug which causes the "track combobox" to contain maaaaaany
   items; the TrackListModel was not cleaned
- small refactoring concerning the formatting of track and disc numbers