proposal to copy nummod into maxima/src/, was: new version of nummod

Hi Barton,

> First, let's all thank Robert for the work he did on the 5.9.2 release.

Thanks. Of course, it was a team effort.

> Second, I have placed a new version of nummod [...]

If there are no objections, I am going to copy this code
into maxima/src/.  nummod is not yet present in the
Maxima code (neither in src nor share).

In summary, there are 7 new functions:
lmin lmax charfun floor ceiling nummod rationalize

and there are 4 functions which reimplement existing functions:
min max featurep compare

min, max, and featurep are backwards-compatible enhancements.
compare is not. However, compare is not called from
any Lisp or Maxima file, and it is not documented,
so it is at worst harmless to redefine it.

best,
Robert Dodier