copy filter-reporting code from AthFilterAlgorithm to FilterReporter
This is essentially a one-to-one copy of the reporting code that is already there, just so that our filter algorithms that rely on filter reporters instead of a filter algorithm base class do so correctly. So far this only works in Athena, but if we ever add a cut flow service in AnalysisBase we can support it there as well.
Two questions:
- should the systematics-aware filters also report to the cut flow service?
- do we really need to be this fault-resistant about not being able to talk to the cut flow service, or can we just fail?