opl-branch TODO list

Needs research:

 * Some instruments have pitch offset down by one octave (eg. #36)
   - what determines this?
 * Strategy when no more voices are available is still wrong
 * Scale levels don't exactly match Vanilla (off-by-one)

Bad MIDIs:

 * deca.wad MAP01
 * gothicdm MAP05
 * Hell Revealed

Other tasks:

 * Menu volume control
 * Pause music
 * Add option to select MIDI type in setup tool