JDF-629 Fixed EJB container error on absent members.

The REST resource now returns a Response instead of a Member.

This ensures that a WebApplicationException is not the cause of an EJBException thrown by the EJB container.

Test this by deploying and pointing the browser to http://localhost:8080/jboss-kitchensink-html5-mobile/rest/members/1 and similar such URLs. http://localhost:8080/jboss-kitchensink-html5-mobile/rest/members/0 should return an existing member. Subsequent requests should not fail as reported in the bug.