#219 - HAL setup now registers a more strict HttpMessageConverter.

Previously we registered a special HttpMessageConverter with a custom ObjectMapper to deploy the HAL customizations. That converter was added to Spring MVC registered HandlerAdapters and registered as the first converter.

In case Spring MVC handled a request with Accept header */* or no Accept header at all, this meant that this converter kicked in and served HAL even for objects that don't need the customizations.

We now restrict the applicability of that special HttpMessageConverter to subtypes of ResourceSupport so that it will only be chosen if the object to render is of such type.