Closes the widget nicely, making sure to clear the graphics scene and release memory.

def close(self):
        """Closes the widget nicely, making sure to clear the graphics scene and release memory."""
        self.ui.graphicsView.close()
        self.scene.clear()
        del self.image
        del self.imageDisp
        super(ImageShowBasicWidget, self).close()
        self.setParent(None)