refactoring and fix

fix a potential dead-lock caused by timer

source/unicode_bidi.cpp

@@ -1,3 +1,17 @@
+/*
+ *	Unicode Bidi-Language Implementation
+ *	Nana C++ Library(http://www.nanapro.org)
+ *	Copyright(C) 2003-2019 Jinhao(cnjinhao@hotmail.com)
+ *
+ *	Distributed under the Boost Software License, Version 1.0.
+ *	(See accompanying file LICENSE_1_0.txt or copy at
+ *	http://www.boost.org/LICENSE_1_0.txt)
+ *
+ *	@file: nana/unicode_bidi.cpp
+ *	@contributors:
+ *		glavangeorge(pr#440)
+
+ */
 #include <nana/unicode_bidi.hpp>
 #include <nana/c++defines.hpp>