Stop the OpenSL buffer queue when stopping the device
Don't use the same buffer segment for enqueueing in OpenSL
Use the 64-bit clamp method when getting the MIDI clock time
Add an extension to pause audio processing
Stop the device when updating parameters, don't close it
Add a flag to specify the device being paused

Used to prevent UpdateDeviceParams from restarting the device, if a new context
is created while paused.
Use ALfontsound_setPropi to set fontsound sample properties

And make sure the loop mode is properly translated for FluidSynth.
Handle fontsound sample types using explicit enum values

Uses AL_MONO_SOFT, AL_RIGHT_SOFT, and AL_LEFT_SOFT. "Linked" samples types
aren't explicitly supported due to being under-defined in the SF2 spec, nor are
ROM samples currently.