Calo towers

Major speed-up of CaloTowersCreator 
in HLT PU 63 its contribution drops from 6% to 1.1%
more gain is possible (also in its users)

Inconsistencies between CaloTower and LeafCandidate persist
(for instance the return type of p4(...) )

negligible regression observed
such as
1004 1821 5928.38 (34.7787,-5.38291,-505.357,5928.38)
vs
1004 1821 5928.38 (34.7787,-5.3829,-505.357,5928.38)