add an error check for incorrect frame size; this will fail some tests but that's the current bug to fix
merge MediaAudioImpl into MediaAudio to aid debugging; add signatures (commented out) for pop/push on audio buffers
fix comments to reflect that we now throw exceptions for interruptions
revise comments
change EAGAIN handling so we return 0 with an incomplete packet.
Attempt to fix SWIG generation problem. Not yet working.
change filtering to allow (1) fixed audio frame sizes to be returned and
(2) EOF handling and EAGAIN handling to be correct. Add tests for both.