class so they all the low-level details of MIDI streaming are kept in
one place.
- Converted the SMF MIDI playback to use the same MIDI streams as MUS
playback.
- Moved MUS playback back into its own thread so that it can continue
uninterrupted if the main thread is too busy to service it in a timely
manner.
- Fixed: The MEVT_* values are not defined shifted into their spot for a
MIDIEVENT, so I need to do it myself.
- Fixed: Pausing a MUS and the changing snd_midivolume caused the paused
notes to become audible.
SVN r784 (trunk)
