Adding a LICENSE file

I love your theme, and I really wanted to make sure that others that enjoyed it as much would be able to use it as well!

I hope you don't mind.

![Screenshot from 2013-04-20 15:51:45](https://f.cloud.github.com/assets/179852/405791/509ad1d4-aa0d-11e2-8ba7-96e71e82ccc5.png)