Modernize PrAlgorithms
- prefer auto
- remove use of BOOST_FOREACH
- prefer range-based for loops
- prefer implicit destructors
- prefer direct member initialization
- prefer emplace_back over push_back
- prefer inheriting from extends over virtual inheritance
- add final
- remove inclusion of unused header Event/TrackFunctor.h
- prefer assignement over hard-wired set of push_backs