Preparation to migrate the Simulation away from barcodes
In this MR:
- added headers needed in the future -- quite likely the future functions in the TruthUtils will use the TruthVertex, so it should be included.
- changed the argument for internal barcode comparison from particleLink to particleLink.cptr().c No real change, just more convenient for the templates, i.e. "->barcode()" vs ".barcode()" call.