Noissue - Eliminate compile warnings in the plugin

src/plugin/NotificationMessage.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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 50 matching lines @@
   ti.hwnd = parentWindow;
   ti.hinst = NULL;
   ti.uId = (UINT_PTR)parentWindow;
   ti.lpszText = const_cast<LPWSTR>(message.c_str());
   GetClientRect(parentWindow, &ti.rect);
 
   LRESULT res = ::SendMessage(toolTipWindow, TTM_ADDTOOL, 0, (LPARAM)&ti);
 
   RECT rect;
   GetWindowRect(parentWindow, &rect);
-  Move(rect.left + (rect.right - rect.left) / 2, rect.top + (rect.bottom - rect.top) / 2);
+  MoveToCenter(rect);
 
   SetTextAndIcon(message, title, icon);
   res = ::SendMessage(toolTipWindow, TTM_TRACKACTIVATE, TRUE, (LPARAM)&ti);
 
   return true;
 }
 
 void NotificationMessage::Hide()
 {
   if (toolTipWindow != 0)
@@ skipping 24 matching lines @@
 
 void NotificationMessage::SetParent(HWND parent)
 {
   parentWindow = parent;
 }
 
 bool NotificationMessage::IsVisible()
 {
   if (toolTipWindow == 0)
     return false;
-  return IsWindowVisible(toolTipWindow);
+  return IsWindowVisible(toolTipWindow) != FALSE;
 }