Grid placeholders

I don't like to put presentational classes in my HTML, such as class="small-5 preffix-1" . This can be avoided in Foundation using mixings, but that usually leads to repeated code. A great way to have the best of both worlds is to use placeholders (as explained by http://ianstormtaylor.com/oocss-plus-sass-is-the-best-way-to-css/ )

I've created placeholders for Foundation grid.