types). Name the keys by number; "center", etc. are confusing
with 7-key. Add secondary scratch (both directions are registered,
so we can use them as menu inputs). Change "back" to "select".
TODO: Only one scratch direction is currently recognized for the actual
track. The input config screen can't handle this many keys (goes off
the screen).
I won't get to fixing the above soon. I wasn't ready to actually add BM
support yet, and I don't want to spend too much time on it before I
add keyed support (which is coming after the sound code is stable) ...