New jail(8) committed

[Jamie Gritton]

I've finally put my jail(8) changes into HEAD.  This new version of jail 
can create jails from a configuration file - see jail.conf(5) for the 
format, as well as some additions to jail(8).  This doesn't mean you 
*have* to use jail.conf, but it's a better way to manage jails than the 
existing rc.conf method.

The plan is for rc.d/jail to start and stop jails as specified in 
/etc/jail.conf, but that's not happening yet - right now it still uses 
the old system, which jail(8) is still compatible with.

There's still more that I want to do with this, but it's time it was 
part of current.

Enjoy :-).

- Jamie