SegFault with second run in visualiser

[Laurie Nevay]

Running more than one event in the visualiser results in a segfault / bad access with the per element histogram pointer in end of event action.

Happens irrespective of output format and only on second run. Irrespective or seed.

[Jochem Snuverink]

Could this be because

1. the AnalysisManager is deleted in BDSRunAction::EndOfRunAction()
2. BDSEventAction keeps a member pointer to the AnalysisManager which is not reset when 1. happens

If this pointer can change during the execution I think they should not be stored in the class, but recalled every time it is used. The overhead is negligible, and the code will actually be clearer (imo).

[Jochem Snuverink]

fixed with commit d9807a4