Modify directory scanning such that directory paths dictate routes.

[totherik]

Previously, directory scanning merely loaded each file. Now when a directory is scanned, each directory and file is used in the creation of the route for a particular file. For example:

routes
 |-user
   |-create.js
   |-list.js 

will result in routes

/user/create
/user/list

while the implementation need only contain:

'use strict';
module.exports = function (router) {
    router.get('/', function (req, res) {
        res.send('ok');
    });
};

Additionally, this PR is a minor refactor with rewritten, cleaner tests.

[grawk]

Looked at test changes and ran tests locally. From that perspective things look good to me. I don't fully understand all the new patterns, so there's the caveat with my thumbs up. But as the code clearly works and is tested ... 👍