Merge remote-tracking branch 'upstream/develop' into develop

Core/Instrument/GaussianBeamFormFactor.cpp

Core/Instrument/GaussianBeamFormFactor.h

Core/Instrument/IBeamFormFactor.cpp

Core/Instrument/IBeamFormFactor.h

Core/Instrument/SquareBeamFormFactor.cpp

Core/Instrument/SquareBeamFormFactor.h

Core/Multilayer/MultiLayer.cpp

Core/Multilayer/MultiLayer.h

Core/Tools/MathFunctions.cpp

Core/Tools/MathFunctions.h

Tests/UnitTests/Core/Other/BeamFootprintTest.h

Tests/UnitTests/Core/Other/testlist.h

Tests/UnitTests/Core/Sample/MultiLayerTest.h

auto/Wrap/doxygen_core.i

auto/Wrap/libBornAgainCore.py

auto/Wrap/libBornAgainCore_wrap.cpp