refactor to avoid usage of global access to material model (OOD)

GUI/View/Realspace/RealSpaceBuilder.cpp

GUI/View/Realspace/RealSpaceBuilder.h

GUI/View/Realspace/RealSpaceBuilderUtils.cpp

GUI/View/Realspace/RealSpaceBuilderUtils.h

GUI/View/Realspace/RealSpaceCanvas.cpp

GUI/View/Realspace/RealSpaceCanvas.h

GUI/View/Realspace/RealSpaceMesoCrystalUtils.cpp

GUI/View/Realspace/RealSpaceMesoCrystalUtils.h

GUI/View/SampleDesigner/RealSpacePanel.cpp

GUI/View/SampleDesigner/RealSpacePanel.h

GUI/View/SampleDesigner/SampleView.cpp

Tests/Unit/GUI/TestRealSpaceBuilderUtils.cpp