Rename ErrorCallback into LogSystem, provide a proper console API

src/AppInfoJsObject.h

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef ADBLOCK_PLUS_APP_INFO_JS_OBJECT_H
 #define ADBLOCK_PLUS_APP_INFO_JS_OBJECT_H
 
 #include <v8.h>
 #include <AdblockPlus/JsEngine.h>
 
 namespace AdblockPlus
 {
   struct AppInfo;
-  class ErrorCallback;
 
   namespace AppInfoJsObject
   {
     JsValuePtr Setup(JsEnginePtr jsEngine, const AppInfo& appInfo, JsValuePtr obj);
   }
 }
 
 #endif