#482 - Add support for Collection+JSON mediatype.

Introduce support for media type application/vnd.collection+json. Collection+JSON doesn't allow metadata at the top, so paging data can't be covered, however, everything else fits.

Also moved a little bit more into Affordance and SpringMvcAffordance to avoid using Spring MVC annotations directly in a given mediatype's AffordanceModel.

Refactored bits of HAL-FORMS to reuse the new PropertyUtils, ensuring Jackson ignore annotations are taken into consideration. Also added MockMVC tests to show HAL-FORMS and Collection+JSON working together, against the same controller.

src/main/java/org/springframework/hateoas/Resource.java

@@ -29,6 +29,7 @@ import com.fasterxml.jackson.annotation.JsonUnwrapped;
  * A simple {@link Resource} wrapping a domain object and adding links to it.
  * 
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 @XmlRootElement
 public class Resource<T> extends ResourceSupport {
@@ -38,7 +39,7 @@ public class Resource<T> extends ResourceSupport {
 	/**
 	 * Creates an empty {@link Resource}.
 	 */
-	Resource() {
+	protected Resource() {
 		this.content = null;
 	}