Wordpress autoloader for plugins and themes

wp-autoloader.php

<?php
/**
 * Autoloader for WordPress plugins and themes
 * http://wordpress.stackexchange.com/a/66484
 */
spl_autoload_register(__NAMESPACE__ . '\\autoload');
function autoload($cls)
{
    $cls = ltrim($cls, '\\');
    if(strpos($cls, __NAMESPACE__) !== 0)
        return;

    $cls = str_replace(__NAMESPACE__, '', $cls);

    $path = PLUGIN_PATH_PATH . 'inc' . 
        str_replace('\\', DIRECTORY_SEPARATOR, $cls) . '.php';

    require_once($path);
}