Rename ErrorCallback into LogSystem, provide a proper console API

src/JsEngine.cpp

 /*
  * 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
@@ skipping 170 matching lines @@
 }
 
 void AdblockPlus::JsEngine::SetWebRequest(AdblockPlus::WebRequestPtr val)
 {
   if (!val)
     throw std::runtime_error("WebRequest cannot be null");
 
   webRequest = val;
 }
 
-AdblockPlus::ErrorCallbackPtr AdblockPlus::JsEngine::GetErrorCallback()
+AdblockPlus::LogSystemPtr AdblockPlus::JsEngine::GetLogSystem()
 {
-  if (!errorCallback)
-    errorCallback.reset(new DefaultErrorCallback());
-  return errorCallback;
+  if (!logSystem)
+    logSystem.reset(new DefaultLogSystem());
+  return logSystem;
 }
 
-void AdblockPlus::JsEngine::SetErrorCallback(AdblockPlus::ErrorCallbackPtr val)
+void AdblockPlus::JsEngine::SetLogSystem(AdblockPlus::LogSystemPtr val)
 {
   if (!val)
-    throw std::runtime_error("ErrorCallback cannot be null");
+    throw std::runtime_error("LogSystem cannot be null");
 
-  errorCallback = val;
+  logSystem = val;
 }
 
 AdblockPlus::JsEngine::Context::Context(const JsEnginePtr jsEngine)
     : locker(jsEngine->isolate), handleScope(),
       contextScope(jsEngine->context)
 {
 }