expander needs testing

[cclark2a]

• gate is not closed on expander notes
• need to add suitable expander tests

[cclark2a]

I was setting the channel count incorrectly, still other bugs preventing basic functionality

[cclark2a]

Rewrote expander to always set all voices on all outputs, and it's better, but still mysteriously changes pitch on gate close. Still investigating.

[cclark2a]

Figured out that I need to write all messages every step to make things work. Duh.