[CM] Variables in R7RS libraries

[bil at ccrma.Stanford.EDU]

I don't want to implement that count-value variable business --
I think it violates lexical scope by turning "count-value"
into a weird symbol macro equivalent to (let-ref experiment 
'count-value).
So you have any number of count-value's floating around, and
if you set! one anywhere, all the rest reflect that --
reminds me of a fortran common block for some reason.