1) Merge in the accounts code that I did for ron. Instead of resetting
   the password file on each reboot, look at the node status to
   determine if the password/group file should be reset. If the
   node is free, reset it. Otherwise, we track changes to the password
   and group file now, so that users can change it and not have their
   changes wiped out at each reboot. I had to do this for the ron
   nodes so that the testbed software would not alter or delete
   already existing accounts; I keep a couple of little dbm files
   listing all the accounts/groups added. The only downside right now
   is if a node is reallocated before it is wiped clean; I plan to add
   an os_teardown phase to experiment termination asap.

2) Add tunnels support. New DB table (tunnels) provides information
   for running vtund to link up to remote nodes. Creates a vtund.conf
   file on the fly, and fires them off. The complication is that you
   cannot do the ifconfigs or the routes until the tunnels are
   connected, so that stuff has to be configured within the vtund.conf
   file on a per tunnel basis. vtund.conf has some sections for
   running commands when tunnels are brought up or down.

3) Damage the routing configuration code that Mike did. To support
   tunnels, as noted above, rc,route is no longer a simple list of
   commands, but a program that adds/dels routes based on the netmask,
   with a special "enable" section for the other stuff. This allows me
   to call it from vtund.conf for up/down on each tunnel'ed
   interfaces, as needed. Quite gross, but no way around it.

4) For remote nodes, add a vnodesetup script, invoked from boss when
   experiments are setup/torndown. This gets the tunnel/route/trafgen
   configuration and runs them. It then goes into the background
   waiting for a death signal, at which time it brings them down and
   cleans out the vnode state.