This change is to essentially prevent people from subclassing Resource and call the default constructor which wrecks the assumption of content never being null. For custom resources extend ResourceSupport.
Added missing license header in ResourcesMixin.
Added Jackson 2 dependencies. Doubly annotated representation model classes with both Jackson 1 and Jackson 2 annotations. Added Integration tests for Jackson 2 marshaling provided by Jon. Polished template.mf.
Added correct equals(…)/hashCode() methods to PagedResource, PageMetadata. Polished toString() methods of ResourceSupport, Resource, Resources and PagedResources. Added factory method to PagedResources to easily create a plain instance from a set of entities.
Introduced Resource and Resources value objects. The former captures single entity instances but adds links to it. The latter does the same for a collection of entities. Added SPI interfaces ResourcePostProcessor and ResourcesPostProcessor to allow manipulating Resource and Resources instances.