[CM] process drift fixed

[Heinrich Taube]

svn has the real-time process drift issue solved, i think. thanks very  
much to neil baylis who both reported the problem and helped fix it.  
he reports that even after 20 minutes the processes are still in lock  
step in both chicken and s7.
hopefully the fix wont cause problems in other situations!


(define (note-cycle endtime keys rate)
   (process with pat = (make-cycle keys)
           while (< (elapsed) endtime)
           do
           (send "mp:midi" #:key (next pat) #:dur rate)
           (wait rate)))

(let* ((k1 (key '(c4 g a bf)))
       (k2 (key '(c2 e g a bf a g e)))
       (stop 1000))
   (sprout (list (note-cycle stop k1 .4)
                 (note-cycle stop k2 .2))
          ))