sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

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

After r193232 rt_tables in vnet.h are no longer indirectly dependent on
the ROUTETABLES kernel option thus there is no need to include opt_route.h
anymore in all consumers of vnet.h and no longer depend on it for module
builds.

Remove the hidden include in flowtable.h as well and leave the two
explicit #includes in ip_input.c and ip_output.c.

Rather than using hidden includes (with cicular dependencies),
directly include only the header files needed. This reduces the
unneeded spamming of various headers into lots of files.

For now, this leaves us with very few modules including vnet.h
and thus needing to depend on opt_route.h.

Reviewed by: brooks, gnn, des, zec, imp
Sponsored by: The FreeBSD Foundation

- Import the HEAD csup code which is the basis for the cvsmode work.

Bitrot: the ethernet parse type is long standard.

Export "ng_ether_enaddr_type" because the ng_bridge type uses it.

Use a consistent style and one much closer to the rest of /usr/src

Build ng_ether(4) KLD.