Backward compatibility between the Ruby version of CMC, PXE and the nodeHandler

1) The handler directory has a new cmc.rb file. Checkout the latest handler/cmc.rb

2) In nodeHandler.rb,

def run(): change CMC::nodeAllOff() to CMC::nodeAllOffSoft()

def shutdown(): change CMC::nodeAllOff() to CMC::nodeAllOffSoft()

3) In experiment.rb,

def Experiment.start(): make changes to send a single CMC call to the entire set instead of sending multiple CMC calls (once for each node). The existing code is in comments and the new code has been explicitly identified.

4) In node.rb,

def powerOn : comment out CMC::nodeOn(x, y)

def powerOff : change CMC::nodeOff to CMC::nodeOffSoft

5) In nodeHandler/src/etc/nodehandler/grid.cfg,

set CMC_URL= "​http://cmc:5012/cmc"

6) In nodeSet.rb,

def pxeImage(image, imageName = nil) : change the string that is assigned to @pxePrefix.The existing code has been commented out and also comments indicate the new code added. The calls to the function setPxeEnv has been commented and an new function setPxeEnvMulti has been implemented.