Add additional cache control headers per RFC 6749 Section 5.1

http://tools.ietf.org/html/rfc6749#section-5.1

"The authorization server MUST include the HTTP "Cache-Control" response header field [RFC2616] with a value of "no-store" in any response containing tokens, credentials, or other sensitive information, as well as the "Pragma" response header field [RFC2616] with a value of "no-cache"."