[CDG5] Mac OS + DSP stuff

[Jason Duerstock]

Not really related to anything worked on here so far, but a bunch of
interesting stuff showed up on bitsavers.org recently:

http://bitsavers.trailing-edge.com/bits/Apple/Mac/mpw/

It looks like a bunch of DSP tools for MPW.  Although the disk images
appear to be rather odd -- it's like someone put an HFS partition
inside a GPT wrapper.  Anyway, if you guys dig into it and find
anything interesting, let me know.  I will do the same.