fixed treatment of units in HepMC format (#175) added Weight to HepMCEvent branch to store the event weight (#173) added Rho branch to store the rho energy density (#176) added random rotation of pile-up events around the z-axis
fixed treatment of units in HepMC format (#175) added Weight to HepMCEvent branch to store the event weight (#173) added Rho branch to store the rho energy density (#176) added random rotation of pile-up events around the z-axis