Convert macros `tmac.XXX' to `XXX.tmac'. Special cases:

Convert macros `tmac.XXX' to `XXX.tmac'.  Special cases:
  tmac.doc.old -> doc-old.tmac
  tmac.an.old  -> an-old.tmac

* tmac/tmac.*: Moved to ...
* tmac/*.tmac: this.
* tmac/man.local: Fix comment.
* tmac/groff_man.man, tmac/groff_markup.man, tmac/groff_mdoc.man,
tmac/groff_me.man, tmac/groff_ms.man, tmac/groff_tmac.man: Updated.
Added some `FILES' sections.  More use of @...@ directives.  Other
minor updates.
* arch/djgpp/README, font/devutf8/NOTES: Updated.
* doc/homepage.ms, doc/groff.texinfo: Updated.
* man/groff.man, man/roff.man: Updated.
* src/devices/grodvi/grodvi.man, src/devices/grolbp/grolbp.man,
src/devices/grolj4/grolj4.man, src/devices/grops/grops.man,
src/devices/grotty/grotty.man: Updated.
* src/preproc/pic/pic.man: Updated.
* src/roff/grog/grog.pl, src/roff/grog/grog.sh: Use -mdoc-old
instead of -mdoc.old.
* src/roff/grog/grog.man: Document -mdoc and -mdoc-old.
* src/roff/nroff/nroff.man: Updated.
* NEWS: Updated.

* tmac/fixmacros.sed, tmac/strip.sed: Add explanatory comment.

* tmac/mm.diff: Removed -- it has no use now since the mm package
is part of groff.

* tmac/*: Removed trailing spaces.

* arch/djgpp/t-groff.bat: Fix GROFF_TMAC_PATH (hyphen.us is now in
the tmac subdirectory also).