Add Musician sources v3.2

These were downloaded from http://stevelitchfield.com/musician.htm
Add a silent note at the end of the piana midi files

Pys60 on the E51 sharply cuts off sound when the midi file ends, even
when the note really needs a bit more time to fade away. By adding a
silent note (same note with velocity 0 and half the duration), the note
nicely fades out.

This also adds a shell script I used to generate the updated midi files.
Allow changing the volume in piano mode

The volume is also saved across restarts in the settings file.