DATAREST-203, DATAREST-75 - Initial support for HAL.

This commit introduces support for HAL rendering and making it the default rendering option. The configuration now registers an additional MappingJackson2HttpMessageConverter with the according HAL modules registered and makes this the default JSON renderer if the default media type is configured to HAL (which it is by default). To change this, set RepositoryRestConfiguration.setDefaultMediaType(…) back to application/json.

Refactored the PersistentEntityJackson2Module to turn the PersistentEntityResource into it's correct shape (turning associations into links) and the delegate to the default rendering, so that the HAL customizations provided by Spring HATEOAS can kick in. Adapted test cases to the change in default representation format.


Upgraded to Jackson 2.3.0, Spring 3.2.6 and Spring HATEOAS 0.9.0.BUILD-SNAPSHOT. Upgraded to Gradle 1.10.
DATAREST-209 - Removed hard dependency on Jackson Hibernate 4 module.

The build script now declares the Jackson Hibernate 4 as optional dependency to avoid being registered in a non-Hibernate environment. Tightened auto-registration checks to also check for Hibernate 4 presence at all.