Binding WSDL to (refactored) SOAP

Here's how the mappings from WSDL to SOAP and from SOAP to transport
work in the case of an in-out MEP.

    * WSDL: An in-out consists of
          o An inbound message transmitted from the client to the server
          o One of
                + An outbound message from the server to the reply endpoint
                + An outbound message from the server to the fault endpoint
    * SOAP: Each part of the MEP is a one-way message transmission.
    * Transport: SOAP defines various bindings to transport-level
      constructs e.g,
          o A binding to transmit a SOAP message via an HTTP POST
          o A binding to transmit a SOAP message via an HTTP response
          o A binding to transmit a SOAP message via email
          o Etc.
    * WSA WSDL Binding identifies the client, server, reply and fault
      endpoints, and therefore the exact bindings of the message
      transmissions, dynamically

E.g., in the existing synchronous case, the inbound message comes as an
HTTP POST.  The server sees that the reply endpoint is anonymous and
chooses to send the response as an HTTP request.

E.g., in the asynchronous HTTP case, the inbound message comes as an
HTTP POST.  The server sees that the reply endpoint is not anonymous. 
It sends an HTTP POST to the reply endpoint.  As part of receiving the
HTTP POST, the reply endpoint sends back an ack.

E.g., in the cell phone case, the inbound message comes as an HTTP
Response.  The server sees that the reply endpoint is anonymous, and
sends back a response as an HTTP POST to the "client" (the same address
that spawned the HTTP Response).  This specialized meaning of
"anonymous" is defined as an extension.