http://www.raywenderlich.com/79046/unity-new-gui-tutorial-part-3
Unity iOS build
Soomla/Admob
https://www.packtpub.com/books/content/creating-simple-gamemanager-using-unity3d
http://www.pencilsquaregames.com/2015/01/reducing-draw-calls-also-named-setpass-calls-on-unity5/
http://wiki.unity3d.com/index.php/Singleton