public static function get()
 {
     if (!isset(self::$instance))
     {
         $c = __CLASS__;
         self::$instance = new $c;
     }
     return self::$instance;
 }
<?
// no direct access
defined('_JEXEC') or die('Restricted index access');
define('JFLT_EXEC', true);
if (!defined('DS'))
{
    define('DS', DIRECTORY_SEPARATOR);
}

// load and inititialize JFT class
require_once(realpath(dirname(__FILE__)) . DS . 'lib' . DS . 'Jflt' . DS . 'jflt.php');
global $jflt;
$jflt = jflt::get();

$headerstuff = $this->getHeadData(); // pega os dados do cabeçalho
//unset($headerstuff['scripts'][$this->baseurl . '/media/system/js/mootools.js']); // remove mootools 1.11
//unset($headerstuff['scripts'][$this->baseurl . '/media/system/js/caption.js']); // remove caption
// Insere o novo mootools
//$headerstuff['scripts'] = array_merge(
//    array('https://ajax.googleapis.com/ajax/libs/mootools/1.3.0/mootools-yui-compressed.js' => 'text/javascript'), $headerstuff['scripts']
//);
$this->setHeadData($headerstuff); // carrega as modificações efetuadas
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="pt-br" lang="pt-br" >

    <head>
        <jdoc:include type="head" />
        <?
        //$this->addScript($jflt->templateUrl . '/js/mootools-core.js');