FS#10324: WAV file output

[Jeff Goode]

Hi RB dev team,

I added a debug/diagnostic tool at FS#10324 which allows creation of WAV 
files of the DSP output for analysis.  Currently it's set up to be built 
into simulators only.

I was hoping that it could be committed to the official build, and would 
appreciate any feedback.

Thanks,
Jeff