refactored test client for simple resuable interaction methods.
1) Added support HATEOAS link testing in test cases. 
2) Made root URI names pural, e.g., users instead of user, to conform
with RESTful best practices doc from APPIGEE
3) Removed harded resource names in server code as much as possible by
making better use of the UriBuilder and UriInfo classes.
4) Test cases now look at repsonse headers and returned entities to
better verify expected results.
5) All URIs returned, structural and transistional, are absolute to
minimize assumptions made by clients.  
6) Helper methods exists in the JerseyResourceTest class for dealing
with absolute URIs.
7) Removed isolation of resources under test to support HATEOAS.