PaStreamFinishedCallback which is called anytime a PaCallback is exited with
anything other than 0. (normal operation) paStreamFinishedCallback handles
stopping the audio stream when we've run to the end of the current selection
or the stream is stopped.
* Add framesPerBuffer to paCallback debug output in preperation for dynamic
buffers.
* Set paPrimeOutputBuffersUsingStreamCallback in Pa_OpenStream to prime the
output buffer using the callback rather than initing with empty space which
is the default.
* Indent paCallback decleration another level.
Originally committed to SVN as r2807.