[tex-k] dvitomp update: support \Black, \Red, and similar colordvi commands

[John Hobby]

The reason why I never implemented dvi specials in dvitomp was mostly
laziness, but I also thought that there wasn't much of a need.

A. I wanted to keep the typesetting capabilities as simple as possible and
   rely on the main part of the MetaPost language for features such as color.
   I should think that most users could just do something like this:
     color Cerulean; Cerulean= (0.0600122, 0.889988, 1.0);
     draw btex This is blue! etex withcolor Cerulean;
     label(image(draw btex This is blue! etex withcolor Cerulean), z0);

B. I have no objection to upgrading dvitomp to handle any reasonably-standardized
   set of specials (including color specials), as long as I don't have to do the
   work.  I thought special-handling was a frighteningly open-ended feature, but
   perhaps that isn't so true any more.

C. I am somewhat concerned about version control.  Are we using .ch files
   to implement things that belong in dvitomp.web or mp.web?  If a feature
   is not system dependent and is or should be implemented in everyone's
   version, then it should be in the main sources and the main version
   number should be increased.

D. There is no prohibition against people other than me touching dvitomp.web
   and mp.web.  I just hope any such changes could be done with reasonable
   regard for version control.

- John Hobby