DATAREST-249 - Prepare next development iteration.
DATAREST-253, DATAREST-254 - Fixed serialization handling of transient properties.

AssociationOmittingSerializerModifier not correctly handles transient properties, which means it's handling null PersistentProperties correctly.

Also, AbstractRepositoryRestController.handleNotReadable(…) is not bound to HttpMessageNotWritableException anymore which caused the former errors to be masked by a Spring MVC exception claiming about the exception handler method not being invokable correctly.