def add_url (self, url, line=0, column=0, page=0, name=u"", base=None):
        """Add new URL to queue."""
        if base:
            base_ref = urlutil.url_norm(base)[0]
        else:
            base_ref = None
        url_data = get_url_from(url, self.recursion_level+1, self.aggregate,
            parent_url=self.url, base_ref=base_ref, line=line, column=column,
            page=page, name=name, parent_content_type=self.content_type)
        self.aggregate.urlqueue.put(url_data)
Add new URL to queue.