Stop dsound properly. (#642)
Stop dsound properly. (#642)

Stopping `dsound `before stopping `audio thread` avoid dsound playing transient glitches between the time audio task is stopped and dsound will be released. These short trailing glitches are particularly audible when captured by a reverb connected on output.

FluidSynth/fluidsynth,FluidSynth/fluidsynth,FluidSynth/fluidsynth,FluidSynth/fluidsynth