[Proposal] Support multiple paginations in 1 page

The problem description: https://github.com/laravel/framework/issues/164
I sugest passing **$pageName** in **paginate()** method.

How to use:
```php
Model1::paginate(15, array('*')); // By default 'page' will be used
Model2::paginate(15, array('*'), 'page2');
```

In views:
```php
$model1_objects->appends('page2', Input::get('page2', 1))->links(); 
...
$model2_objects->appends('page', Input::get('page', 1))->links();
```

Using **appends()** is optional.