rm remnants of SessionModel

GUI/Model/Model/ApplicationModels.h

GUI/View/Common/ItemStackWidget.cpp

GUI/View/Common/ItemStackWidget.h

GUI/View/Fit/FitParameterDelegate.h

GUI/View/Import/RealDataMaskWidget.cpp

GUI/View/Mask/MaskEditorActions.cpp

GUI/View/Mask/MaskEditorCanvas.h

GUI/View/Mask/MaskEditorPropertyPanel.cpp

GUI/View/Mask/MaskResultsPresenter.cpp

GUI/View/Projection/IntensityDataProjectionsWidget.cpp

GUI/View/Projection/ProjectionsEditorActions.cpp

GUI/View/Projection/ProjectionsEditorCanvas.cpp

GUI/View/Projection/ProjectionsEditorCanvas.h

Tests/Unit/GUI/TestDataItems.cpp