GUI: Add NanoGUI

Author: myd7349

README.md

@@ -311,6 +311,7 @@ A curated list of awesome C/C++ frameworks, libraries, resources, and shiny thin
 * [libui](https://github.com/andlabs/libui) - Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports. [MIT]
 * [MyGUI](http://mygui.info/) - Fast, flexible and simple GUI. [MIT]
 * [nana](http://nanapro.org/en-us/) - Nana is a cross-platform library for GUI programming in modern C++ style. [Boost]
+* [NanoGui](https://github.com/wjakob/nanogui) - A minimalistic cross-platform widget library for OpenGL 3.x or higher. [BSD]
 * [nuklear](https://github.com/vurtun/nuklear) - A single-header ANSI C gui library. [PublicDomain]
 * [QCustomPlot](http://qcustomplot.com/) - Qt plotting widget without further dependencies. [GPLv3]
 * [Qwt](http://qwt.sourceforge.net/) - Qt Widgets for Technical Applications. [Own based on LGPL]