[tex-k] [WEB] Integrated webmac.tex for plain TeX, pdfTeX, and XeTeX

[Andreas Scherer]

> Now I'll test it with the full KNUTHware codes.

'webmac.tex' has been fixed for a few boundary cases (bibtex.tex, and
the "chapter numbers" in mf.web and tex.web).  The complete set of (19)
KNUTHware WEB sources can be processed with the 'makeall' script in
various combinations of '--tex=engine' (with 'engine' in
{tex,pdftex,xetex}), '--new' macros instead of TL version of
'webmac.tex', TL '--changes' applied; option '--pdftocfront' does _not_
yet produce clean results except for a handful of codes.  This will be
the next subproject.

Best,
Andreas