To have the ability to add more than one song book to a song will be
helpful for the song importers, since a few formats support more than
one song book, which means we have to take one of the song book and drop
May as list of songbook id's like in the Verse order.
This would have an impact to the GUI. May we could pass the songbook
number and add same gui settings as for authors
State of a Song
This property describes the state of a song. This can be
1 - in progress
2 - Ready
3 - faulty
This could have an Impact to the GUI. May the songs could have different
colors in the media Manager List view (black - ready, yellow - in
progress, orange - faulty). Also there would be the possible to change
the state needed (eg. context menu, button, shortcut, radio button in
the song editor or the like).