invMass to energyBranch Name code duplication

[ldcorpe]

This is not urgent, but there is a duplication of nearly identical code which should be factorised, since otherwise if one wants to add a new energy Branch, one needs to change it ins several places instead of just one.

The two places are:

ECALELF/ZFitter/src/ZFit_class.cc

Line 1175 in 3c7c7fc

TString ZFit_class::GetEnergyVarName(TString invMass_name){

and:

ECALELF/ZFitter/bin/ZFitter.cpp

Line 212 in 3c7c7fc

std::string energyBranchNameFromInvMassName(std::string invMass_var){

[shervin86]

I agree, maybe we should create a library of functions that can be loaded by both.