Build history style & error details

Make history not scroll horizontally
![screen shot 2014-11-12 at 6 36 50 pm](https://cloud.githubusercontent.com/assets/34726/5020800/f185909e-6a9a-11e4-93d3-3a7587501748.png)

Hide the details behind a toggle
![screen shot 2014-11-12 at 6 37 05 pm](https://cloud.githubusercontent.com/assets/34726/5020801/f18b7d6a-6a9a-11e4-93a8-d6bdc8485d22.png)