use a vector instead of a map to make the order of particles deterministic and not depend on the memory layout
This is a problem if more than one primary particle exists.
Now runs with the same randomseed will produce the same result

Fixes crash when unknown particles (e.g. PDG 94) exist in the MCHistory
Should only be a problem if the MCGenerator does not write proper information

Support for multi-threaded Geant4 applications using DDG4Details are described in the release notes.

No code changes. Common code formatting removing tabs, replacing with spaces (tab-size=-2) + emacs reformatting.

First implementation of dipole field, HepMC reader for DDG4 and fix to import constants into DDG4 python