add PV trimmer
add also track_pt_min parameter (consistency check added, in case PV producer and PV comparer have different threshold a LogWarning is raise
add configuration for PVClusterComparer (it should be used as refToPSet_)
add import of PVcomparer PSet
removed commented lines
removed commented lines
PVcomparer PSet is needed, now
fix default initialization
add fillDescriptions
delete unsed beginJob and endJob and change from edm::EDProducer to stream::EDProducer
delete counter (use instead directely the size of the vector)
Merge pull request #3864 from mtosi/from-CMSSW_7_1_X_2014-05-12-0200_PVtrimmer@HLT

Reco -- Primary vertex trimmer (HLT)