Create an ajax response framework that inserts <meta> tags to guard

against UTF-7, and create a $.gallery_autocomplete variant of jQuery's
autocomplete that expects the first line to be a <meta> tag and
discards it.  More complete fix for #1871.

modules/server_add/controllers/admin_server_add.php

@@ -72,6 +72,7 @@ class Admin_Server_Add_Controller extends Admin_Controller {
 
   public function autocomplete() {
     $directories = array();
+
     $path_prefix = Input::instance()->get("q");
     foreach (glob("{$path_prefix}*") as $file) {
       if (is_dir($file) && !is_link($file)) {
@@ -79,7 +80,7 @@ class Admin_Server_Add_Controller extends Admin_Controller {
       }
     }
 
-    print implode("\n", $directories);
+    ajax::response(implode("\n", $directories));
   }
 
   private function _get_admin_form() {