replace 'MaskObject' by 'OverlayItem'

Doc/graph/mask-classes.gv

GUI/Model/Mask/MaskContainerItem.h

GUI/Model/Mask/MaskItems.h

GUI/Model/Mask/MaskListModel.cpp

GUI/Model/Mask/MaskListModel.h

GUI/Model/Mask/OverlayItem.cpp

GUI/Model/Mask/OverlayItem.h

GUI/View/Canvas/ProjectionsEditorCanvas.cpp

GUI/View/Canvas/ProjectionsEditorCanvas.h

GUI/View/Scene/MaskDisplayFactory.cpp

GUI/View/Scene/MaskDisplayFactory.h

GUI/View/Scene/MaskGraphicsScene.cpp

GUI/View/Scene/MaskGraphicsScene.h

GUI/View/Setup/ProjectionsSaver.cpp

GUI/View/Shape/AllMasksDisplay.cpp

GUI/View/Shape/AllMasksDisplay.h

GUI/View/Shape/EllipseDisplay.cpp

GUI/View/Shape/EllipseDisplay.h

GUI/View/Shape/IShapeDisplay.cpp

GUI/View/Shape/IShapeDisplay.h