add lang files to cascading

inc/config_cascade.php

@@ -72,6 +72,11 @@ $config_cascade = array_merge(
                 DOKU_CONF.'plugins.protected.php',
                 ),
             ),
+        'lang' => array(
+            'core'      => array(DOKU_CONF . 'lang/'),
+            'template'  => array(DOKU_CONF . 'plugin_lang/'),
+            'plugin'    => array(DOKU_CONF . 'template_lang/')
+            )
         ),
         $config_cascade
 );