Make the header blue

- edition switch moved to the right, and subscribe out of ‘more’
- new, single style of pop up menus
- new and larger icons
- new colours
- services links moved into mega nav
- smoother meganav open/close animation 

![screen shot 2014-08-05 at 11 03 47](https://cloud.githubusercontent.com/assets/867233/3809780/1077a75a-1c88-11e4-8938-6aec1f5688ad.png)

:point_down: 

![screen shot 2014-08-05 at 11 02 55](https://cloud.githubusercontent.com/assets/867233/3809782/135f2344-1c88-11e4-9825-7c208ef4ad20.png)


I thought scss-lint would be reporting these extra semicolons. If you think we should close mixin content blocks with `};`, then it'd be good to have a linting rule for it.

Personally I think it's nice to distinguish Sass from CSS but I had never seen it in the past, so I'm not sure it would be a natural thing for developers to write.