This is a simple to use framework which we use internally. We decided to make it free for everyone!
https://github.com/dotBunny/Hydrogen/
If you are cloning this repository you will more then likely need to copy it into the working folder of your Unity project, unless you've included it in as a submodule on your own GIT repo.
A good tutorial for submodules can be found here:
http://joncairns.com/2011/10/how-to-use-git-submodules/
If you've downloaded the Asset Store version, its already installed for you :)
The example package can be found on the Unity Asset Store here:
https://www.assetstore.unity3d.com/#/content/14110
It has also been made available via a GIT rep here:
http://github.com/dotBunny/Hydrogen-Examples
Documentation, helpful tips on getting started, and much more can be found at the projects homepage:
Any issues can be reported here:
http://github.com/dotBunny/Hydrogen/issues
We’ve created a channel on Vimeo showing off different parts of Hydrogen, check it out:
http://vimeo.com/channels/hydrogen
Due to time commitments to our normal projects, support may be very limited.