[Openal] Unqueuing all buffers from a stream

[Garin Hiebert]

> AFAIK the source has been stopped, which I'd have thought was all 
> that'd be necessary to yank unprocessed buffers from the queue. Or am 
> I missing/misunderstanding something?
Stopping the source should mark all buffers processed and allow 
unqueueing of all the buffers.  There is apparently an issue with at 
least some versions of the NVIDIA OpenAL library, so if there's a 
possibility you're running on that device then you might want to try 
"Generic Hardware" or "Generic Software" and see what happens.

Garin