- Fix the -FIX-es.

? Have the default bank for channel 9 (10) be 128 so it
    automatically plays drums?  No, that's so GM-ish....

? Detect if the plugin is NOT being run on a SSE-or-similar capable
    processor, or if the output buffers are already 16-byte aligned,
    and if so, skip the extra buffer copy?

~ Would be nice to be able to set the max polyphony, but
    libfluidsynth can't change it once new_fluid_synth() is called.

