Hepmc3 nightly fixes 18122020 part 1

Andrii Verbytskyirequested to merge
averbyts/athena:hepmc3_nightly_fixes_18122020_part_1 into master

In this MR:

  • update the types for HepMC3 compatibility: GenParticle* -> GenParticlePtr and so on.
  • use newGenParticlePtr wrapper
  • use c++11 loops
  • use HepMC::barcode() free function
Edited by Andrii Verbytskyi

Merge request reports