Re-add counter to ParticleMassMonitor to know how many events have a mass within 1 mass sigma, that is defined by the user. The counter is used by the bremsstrahlung test Moore!2373 (merged).
Goes with Moore!2373 (merged), lhcb-datapkg/PRConfig!367 (merged)
FYI: @cmarinbe
Albert Lopez Huertas authored7c1b0484