Breaking news

![screenshot](https://cloud.githubusercontent.com/assets/1147913/3800991/0f73b1fc-1bff-11e4-8840-dfee286b4cb0.png)

Consumes `/breaking-news/lite.json` and decides which item to display from it - if any - based on page section, primary keyword, and the user's histogram of visits to these.
We have [many colours](http://guardian.github.io/guss-colours/) at our disposal, not sure there's a reason why we should have different reds?

If `#bc3f2c` happens to be a variant of the tone-live-1 or tone-live-2 colours, then you can use Sass colour functions (`ligthen()`, `darken()`, `mix()`…)