"Desaturise" neutral colours

- [new] Neutral colours are de-saturised (I removed the saturation component from their HSL equivalent) - 
- [new] Top story background colour is the same as the header's (as per Alex's request)

![screen shot 2014-03-18 at 14 50 48](https://f.cloud.github.com/assets/85783/2448992/c0a02aca-aeac-11e3-9133-fe9c284d7c84.PNG)

![ ](http://media.giphy.com/media/Mi6gE0Qjw2dWM/giphy.gif)