Merge branch 'schedulers-cleanup' into 'master'

GaudiHive/CMakeLists.txt

GaudiHive/options/AtlasMCRecoScenario.py

GaudiHive/options/AtomicAlgSequencerTest.py

GaudiHive/options/AvalancheSchedulerSimpleTest.py

GaudiHive/options/BrunelScenarioAvalancheScheduler.py

GaudiHive/src/AlgoExecutionTask.cpp

GaudiHive/src/AlgoExecutionTask.h

GaudiHive/src/AvalancheSchedulerSvc.cpp

GaudiHive/src/AvalancheSchedulerSvc.h

GaudiHive/src/ForwardSchedulerSvc.cpp

GaudiHive/src/ForwardSchedulerSvc.h

GaudiHive/src/IOBoundAlgTask.cpp

GaudiHive/src/IOBoundAlgTask.h

GaudiKernel/GaudiKernel/ConcurrencyFlags.h