Merge changes to preserve steps with transportation
There is a feature branch (feature/calcuttj_keep_transportation) that includes changes that allow steps with transportation to be saved in the process map, and thus preserved with sparsification.
The relevant 'Adding' methods in MCParticle and MCtrajectory simply take a flag that determines if the point with transportation is saved. Default behavior is to not save, in order to avoid many points being saved in certain situations (i.e. NOvA).