Add more instruments

[ljcool2006]

I've noticed while playing this MIDI, the music seems a bit off. Timidity doesn't have enough instruments to play Passport correctly.

[page200]

Possibly related: for some MIDI files, timidity doesn't play any sound at all, even though other MIDI players play them. Example: https://bitmidi.com/bootup-mid

Where are the instrument sounds stored?