Update neutral PID tools
Include Ecal Digits as input to FutureGammaPi0SeparationTool in protoparticles.py, according to the update of photon PID tools made in Rec!2497 (merged) and LHCb!3166 (merged).
These three merge requests should go together. They are ready to be checked.
Edited by Miriam Calvo Gomez