Add page around licensing content

Follow-up to https://github.com/github/choosealicense.com/issues/97.

![screen shot 2013-12-29 at 1 46 59 am](https://f.cloud.github.com/assets/86842/1819083/d2fee298-705d-11e3-833d-4106e668ebd8.png)

![screen shot 2013-12-29 at 1 47 16 am](https://f.cloud.github.com/assets/86842/1819081/8204272c-705d-11e3-978d-ec001ef2abe5.png)