Various UI tweaks for the History feature.

![screen shot 2014-04-14 at 2 12 58 pm](https://cloud.githubusercontent.com/assets/1495261/2700898/990f93ba-c419-11e3-8f9f-787d43ca9424.png)

![screen shot 2014-04-14 at 2 13 07 pm](https://cloud.githubusercontent.com/assets/1495261/2700899/9cb07db8-c419-11e3-9746-cef7ba651c0d.png)