update GacUI in GUI

1. fix the order of GacUI in GUI section,
2. add license,
3. update the link of GacUI.

Author: chaomai

README.md

@@ -263,6 +263,7 @@ A curated list of awesome C/C++ frameworks, libraries, resources, and shiny thin
 
 * [CEGUI](http://cegui.org.uk/) - Flexible, cross-platform GUI library.
 * [FLTK](http://www.fltk.org/index.php) - Fast, light, cross-platform C++ GUI toolkit. [GPL2]
+* [GacUI](https://github.com/vczh-libraries/GacUI) - GPU Accelerated C++ User Interface, with WYSIWYG developing tools, XML supports, built-in data binding and MVVM features. [Ms-PL]
 * [GTK+](http://www.gtk.org/) - A multi-platform toolkit for creating graphical user interfaces. [LGPL]
 * [gtkmm](http://www.gtkmm.org/en/) - The official C++ interface for the popular GUI library GTK+. [LGPL]
 * [imgui](https://github.com/ocornut/imgui) - Immediate Mode Graphical User Interface with minimal dependencies. [MIT]
@@ -275,7 +276,6 @@ A curated list of awesome C/C++ frameworks, libraries, resources, and shiny thin
 * [PDCurses](http://pdcurses.sourceforge.net/) - Public domain curses library with both source code and pre-compiled library available. [PublicDomain]
 * [Sciter](http://sciter.com/) - Sciter is an embeddable HTML/CSS/scripting engine aimed to be used as an UI layer of modern desktop applications. [Free/Commercial]
 * [wxWidgets](http://wxwidgets.org/) - A C++ library that lets developers create applications for Windows, Mac OS X, Linux and other platforms with a single code base. [Own LGPL]
-* [GacUI](https://github.com/vczh-libraries) - GPU Accelerated C++ User Interface, with WYSIWYG developing tools, XML supports, built-in data binding and MVVM features.
 
 ## Graphics