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

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

Update ipfilter 4.1.28 --> 5.1.2.

Approved by: glebius (mentor)
BSD Licensed by: Darren Reed <darrenr@reed.wattle.id.au> (author)

Merge IPFilter 4.1.23 back to HEAD
See src/contrib/ipfilter/HISTORY for details of changes since 4.1.13

* Someone imported a lot of files with the wrong CVS tag, so lots of files need
that fixed in them....
* Keep unnecessary files out of the non-vendor part of this CVS repository.

This commit was generated by cvs2svn to compensate for changes in r145510,
which included commits to RCS files with non-trunk default branches.

import ipfilter 4.1.8 into the vendor branch