READ: This app is a demo for Unity3D developers. If you don't know what Unity3D is, please don't download this app.
The app demonstrates how to enable and disable the Immersive Mode screen in Unity3D.
This will allow you to show in full screen your game!!!
You can get the code and more info on my blog: http://www.daniel4d.com/blog/free-immersive-mode-android-unity/
If you're a Unity3D developer, and you have any questions about this, feel free to contact me.
NB: Unity 5 builds in Immersive Mode, so this plugin may be obsolete.