Port entire css code base from Less to Sass

This ports all of our CSS from .less based files and compilation to .scss. The main reason for this is so we can utilise Sass's more advanced feature set such as `@content` and how it handles `@media` queries at compilation time to reduce repetition and file size. To specific techniques we are interested in are [responsive grids](https://github.com/csswizardry/csswizardry-grids/blob/master/csswizardry-grids.scss) and [IE friendly mobile first](http://jakearchibald.github.com/sass-ie/) css

CSS compilation is now externally compiled through a Grunt task, *only* when scss files are changed, and not on very page refresh as before. Therefore, we should should see a significant performance boost on compilation times.

I have also included a Bower component.json file so we can begin to dependency manage our CSS modules, such as Normalize.css and pasteup. Hence why there are so many files in this request, as we now have their repo's included (just like we do we js dependecies)

**Once this is merged all dev's will need to ensure they have Ruby and Sass installed. It may also help to clean your sbt project.**

@stephanfowler @commuterjoy @ironsidevsquincy @ahume @mattandrews @gklopper This is a big move so would like your feedback now, or forever hold your peace :smile: