mv XML code to GUI/Support/XML

GUI/Model/BaseItem/SessionItem.h

GUI/Model/Descriptor/AxisProperty.cpp

GUI/Model/Descriptor/DistributionItems.cpp

GUI/Model/Descriptor/DoubleProperty.cpp

GUI/Model/Descriptor/SelectionProperty.h

GUI/Model/Descriptor/UIntProperty.cpp

GUI/Model/Descriptor/VectorProperty.cpp

GUI/Model/Device/AxesItems.cpp

GUI/Model/Device/BackgroundItems.cpp

GUI/Model/Device/BeamAngleItems.cpp

GUI/Model/Device/BeamDistributionItem.cpp

GUI/Model/Device/BeamItems.cpp

GUI/Model/Device/BeamWavelengthItem.cpp

GUI/Model/Device/FootprintItems.cpp

GUI/Model/Device/InstrumentItems.cpp

GUI/Model/Device/InstrumentLibrary.cpp

GUI/Model/Device/MaskItems.cpp

GUI/Model/Device/PointwiseAxisItem.cpp

GUI/Model/Device/RectangularDetectorItem.cpp

GUI/Model/Device/ResolutionFunctionItems.cpp