Remove empty lines from Songs (causes problems otherwise!)
Compatibility reading mode for songs with 0-based lengths
Give Lines as an enumerable instead of creating an array
Add Songwriter and #PREVIEW tag
Read more than 2 voice names
Fix renaming of Editions etc.
Support #SOURCE, #ALBUM
Write #COMMENT
Keep unknown tags/lines
Implement config var
Implement SongWriter and Song.Save()
Fix for SongWriter
Allow #ENDSHORT tags
Detect where Preview and ShortEnd came from
Introduce a function to check whether a given GameMode is available for a song
Use IsGameModeAvail for duet check