WIP: add layout to markdown

quick hack to use the layout in pure markdown pages, it needs to use haml processing first.

current status :

[![click for bigger](http://i.imgur.com/cGAXeQW.png)](http://i.imgur.com/StNyl1I.png)

PS: need to split in several commits, git add -A for now.
starts haml file with four spaces, seems like it works.