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

A new jail(8) with a configuration file, ultimately to replace the work
currently done by /etc/rc.d/jail.

MFC after: 3 months

Update copyright dates and other whitespacey stuff.

Change cfstrings from an STAILQ into a TAILQ to allow commands to be
traversed in reverse order.

Initial work on the new jail(8). There are more features to add, and some
cleaning up to do on existing features, but this is pretty much what the
final product will look like.