entities. All that means is that you can use them independent of
jails by doing something like this in your NS file:

	set link0 [$ns duplex-link $node6 $node9 40Mb 0ms DropTail]

	tb-set-multiplexed $link0 1
	tb-set-useveth     $link0 1

For now, must use OSID FBSD47-JAIL, but that will change when I create
new images. The fallback without useveth is IP aliases like before,
which is nice cause that will work on Linux too.

There are some other minor cleanups included.