Gr-audio-osx updated for Intel Macs


I’ve checked in the changes needed for gr-audio-osx to support both
PPC and Intel Macs using the same codebase.

Another change, moving towards interface-similarity with other audio
modules, is that the Source now auto-detects the desired number of
output streams, and internally does not do computations on any unused

I will work towards moving the Sink to auto-detect, but it’s a bit
more complicated. I will also add support for user-selected audio
input / output device via the second argument … keying on any part
of the device name string.

Thank you to those who’ve provided feedback! - MLD