Prepare JBoss Negotiation for use with JBoss AS7

Now that AS7 has a new security sub-system prepare JBoss Negotiation for use with AS7.

(All custom message parsing can potentially be dropped as we should be able to use the GSSAPI to exchange the messages, also Remoting is being used for the remote calls with SASL support so again we should be able to avoid custom message handling for EJB calls).