Dependency upgrades.

Upgraded to Spring HATEOAS 0.7.0.BUILD-SNAPSHOT. Upgraded Jetty plugin 9.0.3. Removed explicit RequetsMappingHanderMapping as Spring Data REST has DATAREST-83 fixed. Removed @EnableSpringDataWebSupport as it is transparently activated by Spring Data REST.
Adapt rels for new Spring Data REST setup.

Fixed check that cancellation is not allowed after paying.
Upgraded to latest improvements in Spring Data REST and HATEOAS.

Removed explicit annotations preventing export of repository interfaces as SD REST doesn't export non-public repository interfaces anymore.

Switched from field injection to constructor injection in controller classes as Spring HATEOAS dropped the requirement for complete CGLib proxying and thus default constructors. Switched to return HttpEntity instead of ResponseEntity for controller methods.

Cleaned up generics declaration in OrderControllerEventListener to get rid of the raw types warning.
Upgraded to Jackson 2.2.2.
Fixed JUnit artifact id.