fixes issue where preview is not showing on embed browse

Setting the height to auto resolves this. Though some work may need to be done when we do vis/design on the side arrows.

![screen shot 2014-06-26 at 11 39 05 pm](https://cloud.githubusercontent.com/assets/1656824/3408312/c9c4a6f4-fdc5-11e3-84bb-81dea54c391b.png)