Updated to default Zurb 4 layout

This is essentially the layout that is provided if you generate a new
one using `compass create <project-name> -r zurb-foundation --using
foundation`
Updated column layouts.
Added buttons
Added Nav items.

These are implemented but could use the default cursor placements.
Whoops, fixed class names
Merge pull request #7 from matthewforr/master

Added ST2 snippets for Foundation 4