Load translations from an entry point.

def add_entrypoint(self, entry_point_group):
        """Load translations from an entry point."""
        for ep in iter_entry_points(group=entry_point_group):
            if not resource_isdir(ep.module_name, 'translations'):
                continue
            dirname = resource_filename(ep.module_name, 'translations')
            self.add_path(dirname)