Testing of song playback.
Loads time divisions and tempo changes into sequencer.
Converts running status and note on 0 as note off to sane events.
Shifts midi notes 0-127 down by 57, since that is what org.c
currently uses. 0 is "A440."
Default instruments were reduced by 16 to avoid over loading output.
Disabling sequencer does not cause a 'all off' event, and org.c
does not recognize one yet.
I avoided clipping but now the output is too quiet. We need to
amplify it, but also equalize the various instruments and pitches.
When playing the test song (running_hell.mid) I detect a bug in the
sequencer occasionally. Somehow it is not detecting the next event
correctly. >_<