[CM] snd and mzscheme

[Bill Schottstaedt]

Currently, the only Scheme supported by Snd is Guile.  There's no technical reason
that mzscheme is not supported; I even have the macros to do it somewhere,
but people sometimes rub each other the wrong way... (I felt the mzscheme
people "dissed" my work for no reason at all, so I tore out all the mzscheme
code -- if someone else wants to add it, I won't stand in the way).

(You could probably still find the exchange in their mailing list archive,
complete with shocked "how can you use such language, there are
children here", which was true, though not the way they meant.)