Make the Markdown entry mono-spaced

This allows much nicer formatting when working with [tables][] and code blocks

Also See this [example][]

[example]: http://jsfiddle.net/TB5AF/2/
[tables]: http://www.leancrew.com/all-this/2008/08/tables-for-markdown-and-textmate/

The Problem: 
![Screenshot](https://f.cloud.github.com/assets/160412/56472/9377d9ca-5b16-11e2-9bf0-16edd74272f7.png)