DATACMNS-391 - Ensure compatibility with Spring Framework 4.0.

Added Servlet 3.0 dependency for test scope. GenericApplicationContext doesn't refresh automatically in Spring 4.x, so we have to call refresh manually. Added a specific version of populators.xml for Spring 4.x since the jaxb2-marshaller element definition no longer support  the contextPath attribute which changed to context-path.

Original pull request: #52.