Autoload ZendXml from ZF2_PATH

- If ZF2 is installed manually, it's from a tarball, which means that's
  where ZendXml will live.

Author: weierophinney

init_autoloader.php

@@ -34,6 +34,7 @@
 if ($zf2Path) {
     if (isset($loader)) {
         $loader->add('Zend', $zf2Path);
+        $loader->add('ZendXml', $zf2Path);
     } else {
         include $zf2Path . '/Zend/Loader/AutoloaderFactory.php';
         Zend\Loader\AutoloaderFactory::factory(array(