Added AthBeginSeq and AthEndSeq sandwitching around AthAlgSeq to
handle Incident Processing Algorithms

2017-01-25 Steve Farrell <Steven.Farrell@cern.ch>
        * Setting _threaded attribute of PyROOT-bound C++ methods in
          AthAppMgr in order to release the python GIL. The flag is set
          according to ConcurrencyFlags.NumThreads() and is set for the
          initialization, executeRun, and finalization calls.
        * Tagging: AthenaCommon-03-03-21


Former-commit-id: efaefbcf686a87b3b2fec8b5f9e69c55b0c00b7f