Game->SetMIDIVolume and other MIDI control functions in ZScript

[ZoriaRPG]

One guy requested MIDI fadeout script and got an unpleasant response: tampering with MIDI playback on the fly is not possible in ZC at all, sans start/stop in abrupt manner. Perharps something like Game->SetMIDIVolume or similar function may resolve this audio-related issue.

I'd be more inclined to add Audio->Volume[5], as changing the volume for a MIDI stored in the quest file, while it is playing, would not affect its volume if it is playing at the time.

There are a number of things that I eventually want to do under Audio->, however, they are not trivial. I'll note, that the interfaces for each type of audio format, are entirely different, which makes creating some sort of streamlined function set to control them, quite difficult. Users also want loop control, pan control, and other things that are simply infuriating to add to ZScript.