another version of documentation category stuff

Hello,

I've been tinkering with the documentation category stuff again
and you can see the result here.
http://maxima.sourceforge.net/misc/tmp-categories-html/maxima_89.html

At this point the output format has stabilized (i.e. I can't think of
another way to do it) although it would be easy to tinker with
superficial stuff like colors or the size of the category box or whatever.

Many core functions are not categorized. I would want to categorize
all the core stuff before the category stuff appears in a release.
Also, I'm pretty sure the existing categories and category assignments
could be improved.

I am thinking about how this would work in a build. At present the
categories are generated by running some scripts which rework
the Texinfo files before texi2html and reprocess the texi2html
output. (If someone wants to rewrite it in Lisp, or merge it into
texi2html, please go right ahead.) The scripts will probably succeed
only in a Unix-like environment. I don't know if that is a show-stopper:
at present html files are generated and then bundled in the
maxima-5.xx.yy.tar.gz distribution blob, so it is not necessary for
Windows builds to generate the documentation.

The category stuff is really html-specific at present. I can't think
of a useful way to make it work for the text-only .info output.
(Sure, if you look at the .info output with the info browser,
you can follow links, but not in the Maxima describe system.)
I guess it could work in TeX output but I haven't tried it and I'm
pretty sure it would require more work. For info and TeX output
I'm inclined to just suppress the category stuff.

The category stuff is on the category-tagging-branch in CVS.
(Only doc/info files have this branch.)

Any comments on any aspect would be very helpful.

best

Robert Dodier