[Coco] Assembly audio routines

[Brett Gordon]

Yup make sure the low bits are masked.  Its probably fastest to just format
the data before attempting playback (dont mask the bits on the fly)

Ed:  wow.  That's impressive you where able to make 44k on a coco2 from a
sdc!  You must have really interleaved sd access to the extreme to acheive?
Do tell!  Did you totally unroll the data transfer loop or something?

brett