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

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

Remove MAINTAINER line in favor of the entry in src/MAINTAINERS

style.Makefile(5)

Perform a major cleanup of the usr.sbin Makefiles.
These are not perfectly in agreement with each other style-wise, but they
are orders of orders of magnitude more consistent style-wise than before.

beforeinstall -> SCRIPTS.

- Backout botched attempt to introduce MANSECT feature.
- MAN[1-9] -> MAN.

Almost a year exactly from when I first imported mergemaster at freebsdcon,
remove myself as co-maintainer and let Doug handle all the fun.

``mergemaster'' was repo-copied to ``mergemaster.sh'' as it's a shell script.

Delete the original mergemaster and modify Makefile to install mergemaster.sh.

Seen no problem with by: billf
No objections by: Doug Barton

Co-MAINTAINER this module.

mergemaster bmake glue.