Pump up node_admin, adding multiple nodes and -e option. New usage:
Pump up node_admin, adding multiple nodes and -e option. New usage:

	Usage: node_admin [-h] [-n | -w] <on | off> [node ....]
	       node_admin [-h] [-n | -w] -p pid,eid <on | off>
	-h   This message
	-n   Do not reboot node
	-w   Wait for node to come back up if rebooted
	-e   Operate on all nodes in an experiment

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