(1) Applied some fixes due to comments from Larry Breed (easier ones

(1) Applied some fixes due to comments from Larry Breed (easier ones
through chapsec 5.2)

(2) Eliminated use of @footnote---had my doubts about it anyways, and
it's broken in latest texinfo

(3) Introduced *some* use of [] for optional arguments, where
explanation is not simpler by listing cmd w arg and cmd w/out arg
separately.  Still not using @deffn.

(4) Dropped in GPL-2.  NOTE: one of GPL-2 or texinfo is broken; a
couple of headings are too long.  Need patches to texinfo or revision
to GPL-2.