Ensure works with JSONAPI pagination requirements

I'm a bit new to JSONAPI, but it looks like the `meta` key goes away and becomes the `links` key. I tried the new JSONAPIAdapter and doesn't look like this addon plays well with it. Perhaps we can first make the response format overridable, to make the user handle the `links` key themselves and transform it into something we expect. We could also sniff the adapter and try to pick the response format automatically.

Comments welcome because this is just the beginning of my thoughts.