Handle the initial OS and state in a way that Mac thinks is more correct.
Handle the initial OS and state in a way that Mac thinks is more
correct.

Add some more sanity checks when adding nodes:
* Make sure nodes have control-net IP addresses
* Make sure the IP address given to nodes does not conflict
* Don't let them add nodes that have experimental interfaces for which
  we don't know the port

Copy over the cable number and length to the wires table, if the user
gave them.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome