Events for Test Frameworks

Many test frameworks wrap quickcheck, but quickcheck results are reported with Terminal Strings that are then parsed. For example https://github.com/UnkindPartition/tasty/blob/dcbf32078133aa2b569774c417cc49a49f5c573b/quickcheck/Test/Tasty/QuickCheck.hs#L267

It would be much easier to interface with an Event ADT.