Setting up a basic grid

Now that we have Susy installed we can replace our current grid styles using some of the mixins Susy provides. We'll then add a basic grid, similar to that of Bootstrap or Foundation. This will be for the end user to add columns when they need.

We'll then use the built-in Susy mixins and functions to add containers and columns to our layout. This will remove the need for presentational classes within our HTML.