XML option for sites using pre-JSON functionality

I am working on a client site which is on a default cent-os system that comes with php 5.1.7. This PHP version doesn't natively come with the PHP JSON library, but it does come with the SimpleXML library.

I made some modifications to your twitter_pull class that allow for a variable_get to decide if the system should use xml or json. The changes only required the addition of the variable_get, some variable use to point to .xml|.json by variable, and I put the json_decode() into a ->decode() method.
All in all I have ~15 lines changed, and it now works with the xml method, using simplexml.

The new var:

    $format = variable_get('twitter_pull_format','xml');

An example of using the var:

      $url = 'http://api.twitter.com/1/'. urlencode($username) .'/lists/'. urlencode($listname) .'/statuses.'.$format.'?per_page='. $num;

This is the new decode:

  function decode( $data ) {
    switch (variable_get('twitter_pull_format','xml')) {
      case 'json':
        return json_decode($data);
      case 'xml':
        return new SimpleXMLElement( $data );
    }
  }

Attached is the patch. Can you please check it and decide if it is worth while to include it in your source. I know that PHP 5.1.7 is horribly outdated, but the code uses a fallback to JSON, and makes it work on this default CENTOS machine.

(I just realized that I might have had my order of files in my diff statement backwards, if so let me know and I'll run it again.)