Switches the visible widget to the one named *display*

        :param: the name of the desired display to show
        :type: str

def switchDisplay(self, display):
        """Switches the visible widget to the one named *display*

        :param: the name of the desired display to show
        :type: str
        """
        if display in self.displays:
            self.setWidget(self.displays[display])
            self._current = display
        else:
            raise Exception("Undefined display type "+ display)