Remove incorrect comment
Remove adltester

I wasn't testing this, so don't want this as maintenance
burden.
Clean up

- Remove WIN32 audio output code (cannot test this at the moment, anyway)
- Organize headers
Add adljack.cc, a standalone jack softsynth

Avoids the complexity of audioout, midi clocks,
event queues and such.
Make MIDIeventhandler.opl private

Also move Tick() to Update() internally.
Remove ym3812 driver

No use for this driver that provides only OPL2, we need OPL3
Make sampling rate variable