AliEveEventManager

AliEveEventManager
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- In GotoEvent() also accept negative indices, meaning event from the
  end of the file.
- In GotoEvent(), when ESD is the primary data-source, call Refresh()
  to get updated tree information.
- In EventNext/Prev() now cycle around the available event range.
- Add method Int_t GetMaxEventId().

event_first.C, event_last.C
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New macros that navigate to first/last event.