Use long track views in GaudiAllenForwardToV2Tracks

Changes GaudiAllenForwardToV2Tracks to use MultiEventBasicParticles instead of the old event model. See #396 (closed).

The old track converter also copied a track state at the SciFi, but this is not included with SciFi tracks in the new event model. If this is important, we should add a pointer to it to the SciFi track view.

Tested with allen_gaudi_forward.py and Moore!2042 (merged) with identical track checker results: thboettc_track_converter.txt, master.txt