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
These unsigned int <-> int conversions are not necessary, together with the else-if part below (another piece that can be easily factorized). Not a big deal but still not nice (the code is short anyway so probably fine).