Update of PDF reweighting supporting MadGraph use case, use first PDF as default/reference
Merge pull request #78 from fabiocos/70X-201307111053

Update of PDF reweighting supporting MadGraph use case, use first PDF as...
Merge branch 'CMSSW_7_0_X' of https://github.com/cms-sw/cmssw into threadedServiceCallbackInterface
 Further progress modifying service callbacks for the threaded Framework
Further progress modifying service callbacks for the threaded Framework