Handsoap.store_raw_reponse - option for storing raw_xml before parsing

We use SAX for some specific queries with heavy-parsing. Standart handsoap-flow(Nokogiri::XML(or whatever else ::XML), then wsdl xpath parsing, then **to_xml** to produce input for SAX) can be very pricy performance-wise. I'd like to add option for storing raw response and neutralizing to_xml() performance damage on useless xml-rebuilding. Default behaviour left intact.

Edit: Maybe it's a little silly with http_response lying around, but i think it's cleaner that way.