Use _links instead of unrendered embedded entity

[nobesnickr]

This is an exploratory pull request to get feedback and explore a solution

Adding option to use the rendered resources _link object for related/embedded entities when render
embedded resources is set to false.

[weierophinney]

I like this idea. Because it's based off a setting in the helper, individual controllers can also opt-in to the workflow, allowing keeping the original behavior as the default, but selectively opting into the new behavior as particular resources require it.

A few things:

• Please rebase.
• Please add tests.

Thanks!

[Wilt]

We also didn't like the unrendered embedded entity solution and wanted to use links instead.

In the end we solved this by linking all related resources (embedded and not embedded ones). In our current solution we don't have to worry at all about wheter a resource is embedded or not, since links for all related resources are always included in the response. If client needs the resource it checks whether it is embedded if not, there is always the link that can be used for resolving it...

Maybe this is a nice (and more easily implementable) alternative solution...

BTW this issue is very much related to a previous issue: #118

We are using doctrine, and we managed to take this solution to the level where proxies (entities not resolved from the database) are always linked (using the entity id from the proxy) and resolved resources are embedded only once (every other instance is linked).

If we want to add an entity into our HAL response all we need to do is add fetch-join in our entity repository for the entity that we are interested in and it is automatically embedded in the response (we get a a full entity not a proxy, thus it will be embedded)...

[weierophinney]

Closing due to inactivity, and conflicts.