Hepmc3 nightly fixes 20122020 part 1 tracking

In this MR towards migration of tracking to HepMC3

• Update types, e.g. GenParticle* -> GenParticlePtr
• Use std:: explicitly
• Use c++11 loops to loop over particles
• Use stl containers for HepMC3, e.g. vtx->particles_out_size() -> vtx->particles_out().size()
• Use free functions HepMC:barcode()