Save all the figures to a file.

def save_all_figures_as(self):
        """Save all the figures to a file."""
        self.redirect_stdio.emit(False)
        dirname = getexistingdirectory(self, caption='Save all figures',
                                       basedir=getcwd_or_home())
        self.redirect_stdio.emit(True)
        if dirname:
            return self.save_all_figures_todir(dirname)