Set all progress bars to zero and hide them.

def reset_bars(self):
        """
        Set all progress bars to zero and hide them.
        """
        self.url_progressbar.reset()
        self.url_progressbar.show([0, 0])

        self.issn_progressbar.reset()

        self.urlbox_error.reset()
        self.issnbox_error.reset()

        InputController._reset_typeaheads()