Fix for : documentation iframe does not scale to 100% height

When you click on a documentation link in the halbrowser it opens this documentation in an iframe in the right hand column. 

On recent versions of safari / firefox / chrome on the mac this iframe is not scaled to 100% height despite the following css being applied to it

    .documentation iframe { width: 100%; height: 100%; }

This will work in quirks mode but, because an html5 doc type is used it does not because by default the height of an element is auto and you can't take a percentage from that  

![screen shot 2015-01-01 at 18 22 25](https://cloud.githubusercontent.com/assets/133639/5592786/3f7e0690-91e3-11e4-87fe-8c8b610fe957.png)