Remove some aborts that don't really need to be.

Enforce PatchPrimaryKey sanity at the type level rather than attempting to
check for it everywhere.

Remove dead file.
Support stepping bank by shift+scroll/arrow.
MIDI bounce.
Tidy up autowaf.py (noop).
No need to yell.
Nuke user CFLAGS/CXXFLAGS if debug is set.
Mute automation via normal mute button.