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
I did not test it with single precision, but given that there are matrix inversions and matrix solve operations involved, there is some motivation for double precision.  (numerical tests of the derivatives are also used to decide which indices to activate/deactivate at each iteration)