This commit adds a feature to the multisource MIDI drivers which allows setting
a default value for most controllers. This default is then applied at the start
of every new track, which ensures controllers are in the correct state.
This can be used for games which use some controller, but do not reset it at
the start of each track, which can lead to incorrect playback.
This adds a timer proc to the null multisource MIDI driver to drive the fading
process. The null driver does not have any audio to fade, but without this the
fades will just hang and isFading will remain true. The fades are now
effectively timers so game behavior will remain consistent whether MIDI is
turned on or off.
Eugene Sandulenko
Coen Rampen
Orgad Shaneh