Added support for nesting collection arrays with paths.

This change allows users to represent their folder structure better when creating collections. The alternative is to add the folder structure in as the array key, however this method requires minimal structural changes to the code, and is fully backwards compatible.

Example structure would be:
```
array(
    'angular' => array(
        'path' => 'views/worker/home',
            'app.js',
            'factories' => array(
                'path' => 'factories',
                'Address.js',
            ),
            'directives' => array(
                'path' => 'directives',
                'signature.js',
            ),
            'controllers' => array(
                'path' => 'controllers',
                'JobController.js',
            ),
    ),
)
```

This becomes quite useful if you have a large number of files in each folder.