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

mdoc: order prologue macros consistently by Dd/Dt/Os

Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.

Reviewed by: ru
Approved by: philip, ed (mentors)

Mechanically kill hard sentence breaks.

The .Fn function

mdoc(7) police: Use the new .In macro for #include statements.

Prepare for mdoc(7)NG.

Introduce .Lb macro to libutil manpages
Sort .Nm values in some manpages
Remove explicit note about compiling with -lutil, it's implicitly
declared by .Lb macro now.

$Id$ -> $FreeBSD$

If given host.domain:nn[.nn], trimdomain() now reduces it to
host:nn[.nn] (if the domain is the same as the local one).

Tidy up trimdomain() and document it.
Don't truncate one byte short of the passed length.