- OPL3: Added support to change the samplerate of the generator.
- SDL sound: convert wave packet to 16 Bit signed stereo format.
- Increased the maximum size of a single wave packet for playbck/recording.
The code currently only works with the SDL sound output module and at 44100 Hz,
with 16 bit stereo signed little endian format. FM volume control and
save/restore support are not implemented yet. The legacy code for generating
MIDI notes still works and will be removed when mixing support is implemented
in all sound modules.