New Ecal Local Reconstruction with Multifit

Adds additional EcalUncalibRecHitWorker for MultiFit (using Fast NNLS algorithm) and modifies appropriate sequences to activate it by default.

@argiro @emanueledimarco
The code in this loop and in  src/EcalUncalibRecHitMultiFitAlgo.cc  (loop) is nearly identical - could be factorized better (by the way, why do you prefer to have the code here in a header file?).