fixing divide by zero bug
adding RegressionData class which will calculate all regression input variables rather than code copy and pastes as is currently
adding function to create the input vector & some small fixes
few bug fixes
rename of class from RegressionData to EcalRegressionData
rename complete of RegressionData-> EcalRegressionData
intermediate testing version to verfiy the input vector greated with EcalRegressionData is identical to the existing one
updating RegressionHelper to use EcalRegressionData
moving EcalRegressionData to EgammaTools as its not electron specific
updating to new location of header files
adding a filler function when the vertex collection isnt availible
intermediate debug version to ensure that input remains the same
making PhotonProducer pick up variables from the same code as the regression code, this changed what is stored but hopefully for the better
re-factoring BaselinePFSCRegression to reduce code duplication
making the dR comparision  dR2
fixing seg fault bug
fixing sigmaIEtaIPhi miss assigment
reverting sigmaIEtaIPhi defination to what it was for photons, meaning we keep two different definations of this variable and we'll fix this silly mess in 73X
Merge pull request #5423 from Sam-Harper/ECALRegressionRefactor

Ecal regression refactor