Pull Request 2 Dev 1.1

sorry I failed to see a while ago, L30 ~ 41 seem to be repeated on L73 ~ 84. I think it's better to create a method for this to avoid duplicate code. Since it returns to values, maybe we can do this
```
list($where, $where_params) = $this->filter($filter, $where, $user_id);

public function filter($filter, $where, $user_id)
{
    $where_params = array($this->thread_id, $user_id);
    switch($filter) {
        case 'My Comments':
             $where .= ' AND u.user_id = ?';
             break;
         case 'Other people\'s Comments':
             $where .= 'AND u.user_id != ?';
             break;
         default:
             $where_params = array($this->thread_id);
             break;
    }
    return array($where, $where_params);
}
```