Merge branch 'symlinks-20170420' into 'master'

Control/AthContainers/AthContainers/AuxElement.h

Control/AthenaBaseComps/AthenaBaseComps/AthAlgorithm.h

...l/AthenaBaseComps/AthenaBaseComps/AthReentrantAlgorithm.h

Control/AthenaBaseComps/CMakeLists.txt

Control/AthenaBaseComps/share/AthAlgorithmDHUpdate_test.ref

Control/AthenaBaseComps/share/AthAlgorithm_test.ref

Control/AthenaBaseComps/src/AthAlgorithm.cxx

Control/AthenaBaseComps/src/AthAlgorithmDHUpdate.cxx

Control/AthenaBaseComps/src/AthAlgorithmDHUpdate.h

Control/AthenaBaseComps/src/AthReentrantAlgorithm.cxx

Control/AthenaBaseComps/test/AthAlgorithmDHUpdate_test.cxx

Control/AthenaBaseComps/test/AthAlgorithm_test.cxx

Control/AthenaBaseComps/test/AthReentrantAlgorithm_test.cxx

Control/DataModelTest/DataModelRunTests/CMakeLists.txt

...taModelTest/DataModelRunTests/share/xAODTestSymlinks1.ref

...ModelTest/DataModelRunTests/share/xAODTestSymlinks1MT.ref

...delTest/DataModelRunTests/share/xAODTestSymlinks1MT_jo.py

...ModelTest/DataModelRunTests/share/xAODTestSymlinks1_jo.py

...taModelTest/DataModelRunTests/share/xAODTestSymlinks2.ref

...ModelTest/DataModelRunTests/share/xAODTestSymlinks2MT.ref