Service references do not serialize according to SCA spec

After a service reference has been serialized and deserialized, it no longer supports calls using binding.ws.
Indeed, service references can sometimes not even be deserialized.

The attached test case produces a WSDL generation error during the deserialization stage
(i. e. before making any service call) because no WSDL definition is found for
the deserialized binding.

I attach modified versions of two Tuscany samples. In helloworld-ws-service-secure
I have modified the definitions.xml to use BasicAuthenticationPolicySet, as in my
original setup with SAP. In helloworld-ws-reference-secure I have split the
HelloWorldService interface into a part referring to the external web service,
and a part containing additional methods that attempt the remote call while
first serializing the embedded reference. I have deleted the test class
just tested the Socket connection.

You can try starting the service component with "ant run" and then manually
starting (no build target) helloworld.HelloWorldClientTestCase in the client component.
This test case contains two new tests, one with "normal" serialization, one with
coding for explicit XML serialization.

I have added some elements to the composite file and some annotations to the coding
(both hopefully redundant) in order to get clearer about the code structure.