Allow Illuminate\Support\Fluent to implement ArrayableInterface and JsonableInterface.

With this changes you can now do multiple stuff with `Illuminate\Support\Fluent`.

```php

Route::get('/', function() {
     $data = new Illuminate\Support\Fluent(['laravel' => 'awesome']);

     return Response::json($data, 200);
});
```

```php

use Illuminate\Support\Collection;
use Illuminate\Support\Fluent;

Route::get('/', function() {
    $collection = new Collection([
        new Fluent(['name' => 'Taylor Otwell']),
        new Fluent(['name' => 'Dayle Reese']),
    ]);

    return $collection;
});
```


Signed-off-by: crynobone <crynobone@gmail.com>