Include first cut at instructions for man pages in docguide.sgml.
Fix markup.

No big deal; fixed lots of other markup at the same time.
Bigest change: make sure there is no whitespace
 in front of <term> contents.
This will probably help the other output types too.

that it doesn't crash when processing a utility statement.

a shared library, not just when installing it.

unfortunate considering that several subdirectory makefiles were counting
on it to do so...

Add detail on exact interpretation of "concatenated date"
 for various lengths.

Split management chapter from start-ag.sgml to manage-ag.sgml.