Issue 261 - FilterNotifier doesn`t support listeners removing themselves when triggered

lib/filterNotifier.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 48 matching lines @@
    *                 "subscription.added", "subscription.removed",
    *                 "subscription.disabled", "subscription.title",
    *                 "subscription.lastDownload", "subscription.downloadStatus",
    *                 "subscription.homepage", "subscription.updated",
    *                 "filter.added", "filter.removed", "filter.moved",
    *                 "filter.disabled", "filter.hitCount", "filter.lastHit")
    * @param {Subscription|Filter} item item that the change applies to
    */
   triggerListeners: function(action, item, param1, param2, param3)
   {
-    for each (let listener in listeners)
+    let list = listeners.slice();
+    for each (let listener in list)
       listener(action, item, param1, param2, param3);
   }
 };