[CM] Two issues

[Bill Schottstaedt]

> #1.  Is the square-wave generator broken?

yes -- I forgot to initialize the width field.  Should be ok now.

> (setf (mus-width wave) some-num)-reports that there is no
> setf for mus-width.

I think I messed up a merge somewhere -- run.lisp doesn't
have it, but cmus.lisp does -- will check.

> are the waveforms produced by square-wave, triangle-wwave,
> and sawtooth-wave band-limited?

no.