Scifi: New event model
The changes in the event model correspond to JIRA tasks: LHCBSCIFI-79 LHCBSCIFI-80
The default simulation is switched to the detailed digitisation. This is about 2 times faster that the current improved digitisation.
See also the presentation in the Upgrade simulation meeting on 07/03/2017: https://indico.cern.ch/event/577909/contributions/2491068/attachments/1423211/2182939/UpgradeSimulation.pdf
This MR goes together with: LHCb!622 (merged)