Merge branch 'ThreadBug'

App/src/TestMesoCrystal1.cpp

Core/Algorithms/src/DWBASimulation.cpp

Core/Algorithms/src/MultiLayerRoughnessDWBASimulation.cpp

Core/Algorithms/src/Simulation.cpp

Tests/FunctionalTests/TestCore/CMakeLists.txt

Tests/FunctionalTests/TestPyCore/CMakeLists.txt

Tests/ReferenceData/BornAgain/mesocrystal1_reference.txt.gz

...ceData/BornAgain/mesocrystal1_reference_v2_nphi180.txt.gz

...enceData/BornAgain/mesocrystal1_reference_v2_nphi2.txt.gz