another specialized mbuf type in the process. Also clean up some
of the cruft surrounding IPFW, multicast routing, RSVP, and other
ill-explored corners.
work reliably yet (I've had panics), but it does seem to occasionally
be able to transmit and receive syntactically-correct packets.
Also fixes one of if_ethersubr.c's legion style bugs, and removes
the hostcache code from standard kernels---the code that depends on it
is not going to happen any time soon, I'm afraid.