Style kickers for facia-cards

- Apply colour to media kickers and bylines
- Refactor the way we apply colour to tones that have white text by default

![screen shot 2014-10-06 at 11 37 18](https://cloud.githubusercontent.com/assets/1607666/4524455/a812d502-4d44-11e4-8c0e-e56578d130e6.png)

Above we set the default link colour for `.tone-media a` as #ffffff