Add velo lumi counters to HLT2
Adds all velo lumi counters currently implemented in Allen.
Decoding-based counters are identical between the two implementations.
Reco-based counters have some small (<~10%) differences due to reconstruction differences.
As a 1kHz lumi line is not yet implemented at HLT2, all counters are added to the HLT2 30kHz lumi line.
The pseudo-randomly selected PV used for the VeloVertex{X,Y,Z} counters was previously chosen by eventNumber%numVertices. For the HLT2 counters the sum of the integer parts of the absolute Z coordinates of all PVs in the event is used in place of the event number.
Goes with Moore!2976 (merged)