Hepmc3 nightly fixes 28112020 part 1
In this MR:
- use more
auto
for the compatibility with HepMC3 in the loops. - Use
std::
- Use free functions, e.g.
HepMC::signal_process_id
for HepMC3 compatibility
In this MR:
auto
for the compatibility with HepMC3 in the loops.std::
HepMC::signal_process_id
for HepMC3 compatibility