Updates

Make the site look more Guardian by stealing Membership's styles. Still needs a little work I think though. Also reorganises things a little so the Content API stuff is namespaced under `/content-api` and removes `beta.` from documentation URLs.

The diff is pretty much impossible to read, but here are some screenshots (sadly not with the right fonts though...)

![screen shot 2014-10-17 at 17 12 19](https://cloud.githubusercontent.com/assets/896707/4682047/ae8fd088-5618-11e4-866c-7d3f220d451b.png)
![screen shot 2014-10-17 at 17 12 36](https://cloud.githubusercontent.com/assets/896707/4682048/ae9ab6f6-5618-11e4-8cc4-041e10bc13b2.png)

:star2: :station: