code: function (handler, ns, name, type, id)
      {
          var hand = new Strophe.Handler(handler, ns, name, type, id);
          hand.user = false;
          this.addHandlers.push(hand);
          return hand;
      }
docs: PrivateFunction: _addSysHandler
  _Private_ function to add a system level stanza handler.
  
  This function is used to add a Strophe.Handler for the
  library code.  System stanza handlers are allowed to run before
  authentication is complete.
  
  Parameters:
  (Function) handler - The callback function.
  (String) ns - The namespace to match.
  (String) name - The stanza name to match.
  (String) type - The stanza type attribute to match.
  (String) id - The stanza id attribute to match.