[Proposal] Pagination processing is not perfect

Custom Paginator object, not necessarily all elements of an object;

```php
$items = array(.....);
$paginator = Paginator::make($items, $totalItems, $perPage);

...

API::reponse()->array($paginator);
```

![image](https://cloud.githubusercontent.com/assets/1472352/5388423/66d8309a-8125-11e4-8266-e6b118c61ffa.png)