Identity next

This PR updates the GitHub branding to match our recent update. Screenshots...

Header:
![Screen Shot 2013-04-17 at 12 55 20 AM](https://f.cloud.github.com/assets/296432/388901/db62ab70-a6e8-11e2-9512-03a53ec32fda.png)

Footer:
![Screen Shot 2013-04-17 at 12 55 39 AM](https://f.cloud.github.com/assets/296432/388911/13876cfc-a6e9-11e2-8b9c-878c985a79b4.png)