[CM] thread progress report

[Bill Schottstaedt]

Some first impressions of Snd/CLM and threads: on a machine with
2 quad-core 3.0 Ghz 86-64 processors (8 "cores"), I can currently
get with-threaded-sound to run about 4 to 6 times faster than 
with-sound, and multichannel edits (filter-channel) run 6 to 8
times faster.  I'm still chasing race conditions and so on, but this
looks promising.  Also, if you have 8 GBytes or more RAM, you
can now use that 2^32 element table-lookup you've always
wanted -- I think all vct, sound-data, and clm table sizes can
be off_t's.  Use mus-fft for an fft in that size range (and take
a vacation while it computes).