Some cleanup for HepMCAnalysis, bugfixes and preparation for possible usage with HepMC3
In this MR:
- split the interface in a way that passing events from storage, event preparation and analysis are performed in separate transition units. This makes the code much clearer, modular and allows to switch to HePMC3 very easy.
- fixed the situation when the events from storage are modified. Now a copy of events is passed.
- explicit usage of std:: namespace
- remove unused headers
- explicit list of used functions from MCUtils in the MC namespace
Edited by Andrii Verbytskyi