Rewrote lsystems music generator to be more lsystemsy.

Previously had tokens resolve to terminals like a standard CFG, but that
doesn't allow for variable generations.

Current output sounds like *something*, but more random notes than
music. -POLM
Rewrote L-systems again to be more musical.

Using a queue to push state and then play it when popping later added a
lot of structure, as did shifting notes up and down rather than using
fixed ones. -POLM