Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove trailing whitespace per mdoc lint warning

Disussed with: gavin
No objection from: doc
Approved by: joel
MFC after: 3 days

mdoc: move CAVEATS, BUGS and SECURITY CONSIDERATIONS sections to the
bottom of the manpages and order them consistently.

GNU groff doesn't care about the ordering, and doesn't even mention
CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put
them.

Found by: mdocml lint run
Reviewed by: ru

Bump .Dd for r1.5; fix grammatical problem.

Specify the correct way to modify this file, and warn that the
user should not depend on the internal variables documented in
this man page.

MFC After: 2 weeks

Assorted markup, grammar, and spelling fixes.

This manual page will not first appear in 4.10 as RELENG_4 has a different
version of the adduser utility.

Noticed by: simon

Fix today's faux pas by:

Removing the -compact option passed to .Bl macro to avoid useless .Pp macros;
Adding a missing period;
Using .Xr with .Nd since makewhatis(1) has no support for cases where the Xref is absent.

Informed by: ru

Add an adduser.conf manual page.
Hook it to the build in Makefile.
Xref from adduser.8.
Update adduser.8's BUGS section.
Bump the date on adduser.8.