Enabling nested resources.

Although I couldn't find Barista documentation for nested resources, the code is there and when used in the correct way, produces nested resource routes. The only hiccup is in the geddy templates/helpers/action.js where it checks for the non-nested (:format) url param. In the event you nest a Page model resource within a Book model resource, the url would be generated like so: /books/:book_id(.:book_format)/pages and so on.