Fixing some DESCRIBE glitches



I have tried to fix some DESCRIBE related problems, viz.

[Maxima] xmaxima + cmucl, sbcl
http://www.math.utexas.edu/pipermail/maxima/2004/007109.html

Actually, the problem with missing prompts is not xmaxima specific.

A remaining oddity is that CLISP + xmaxima sometimes prints additional
prompts.

Apparently, under xmaxima, the list of numbers passed to DESCRIBE must
end with a semicolon.

[ maxima-Bugs-902792 ] describe interaction parser not robust
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=902792&group_id=4933

Embedded newlines still truncate the input.

[ maxima-Bugs-857171 ] variable needs to be quoted for DESCRIBE to work
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=857171&group_id=4933

This change might be controversial since it implies that, e.g.
describe(%) will give you a list of symbols with a `%' in the name.

Also, I have removed cl-info's dependency on the maxima package by
defining cl-info::*prompt-prefix* and cl-info::*prompt-suffix* and
binding them in $describe.

Note that this patch does not affect a GCL based Maxima (for which we
import the necessary functionality from the "SYSTEM" package).

The patches are at

http://members.inode.at/wjenkner/maxima/cl-info.lisp.diff

http://members.inode.at/wjenkner/maxima/macdes.lisp.diff

Wolfgang