Better Instrument Names

Improved instrument name retrieval; it now checks all instrument change events upon load, and names them based on that.

This is actually more accurate than MidiEditor, which shows many tracks as Acoustic Grand Piano, despite those tracks having a change event that makes them into another instrument later

You can use these to filter out things that lute can't play well, such as strings, choirs, etc.

Also, now automatically disables the Glockenspiel (drums) track on song load (for songs that don't have saved settings)