[CM] tap fixed - patch to tankrev.scm

[bil at ccrma.Stanford.EDU]

The problem (as I have discovered by building a
machine to change the imaginary component of my
time-line) is that as you travel vertically in
time, so to speak, you impinge on others' time-lines,
becoming a different person -- disconcerting!
Now I know why I feel like a stranger to myself
at age 20.  But at least this gives a new way
to write musical loops.