Magallanes/Mage/Autoload.php

<?php
class Mage_Autoload
{
    public static function autoload($className)
    {
        $baseDir = dirname(dirname(__FILE__));
        $classFile = $baseDir . '/' . str_replace('_', '/', $className . '.php');
        require_once $classFile;
    }

    public static function isLoadable($className)
    {
        $baseDir = dirname(dirname(__FILE__));
        $classFile = $baseDir . '/' . str_replace('_', '/', $className . '.php');
        return (file_exists($classFile) && is_readable($classFile));
    }

    public static function loadUserTask($taskName)
    {
        $classFile = '.mage/tasks/' . ucfirst($taskName) . '.php';
        require_once $classFile;
    }
}