Nested included resources filters

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Description

Hi guys, I'm sorry about how this issue is looking, don't have time to make it better.
Currently, (checked on 0.9.5, and it's probably the same on 0.9.7) filtering on nested resources works only for 1 level deep inclusion, i.e. included_resource.filter_key. I made some monkey-patches in my app, to make it work with nested resources inclusion, i.e. included_resource.another_included_resource.filter_key.
Also, I did some changes to make filters work with has_one relationships.

The code can be a little bit messy, but it's working, at least for my project. No blame, please :)

The code is here: https://gist.github.com/RoM4iK/1ce4eab45ed0ceafa8728ed487ccddbb

Commencez par examiner le Gist lié et localiser le point d’entrée existant du filtrage des ressources dans le dépôt. Comparez le comportement actuel des ressources imbriquées sur un seul niveau avec l’imbrication plus profonde demandée et les relations has_one. Le travail est terminé lorsque les filtres imbriqués fonctionnent à plusieurs niveaux d’inclusion, y compris pour les ressources has_one, et que les tests du projet couvrent ce comportement.