removing unnecessary listeners on init

frontend-js/src/main/js/ServerConnector.js

@@ -57,6 +57,16 @@ ServerConnector.init = function() {
   self._loggedUser = undefined;
   self._serverBaseUrl = undefined;
 
+  var listeners = self.getListeners("onDataLoadStart");
+  for (var i = 0; i < listeners.length; i++) {
+    self.removeListener("onDataLoadStart", listeners[i]);
+  }
+
+  var listeners = self.getListeners("onDataLoadStop");
+  for (var i = 0; i < listeners.length; i++) {
+    self.removeListener("onDataLoadStop", listeners[i]);
+  }
+
 };
 ServerConnector.registerListenerType("onDataLoadStart");
 ServerConnector.registerListenerType("onDataLoadStop");