Fixes to RHadron simulation
Most fixes affect the simulation of squark R-hadrons, but some affect gluino R-hadrons as well. The function to calculate baryon number was just wrong (only gave +1 or 0, and didn't correctly handle several classes of particles). The calculation of strangeness was also inconsistent.
All fixed now, validated, and tested through to plots of the simulation that have been made public in ATL-PHYS-PUB-2019-019
cc @leejr , @kpachal , @hoide , @shanisch , @oabouzei , @ekuwertz