add release_date and format date string

issue #272

How does this look? 

before
![iss272](https://f.cloud.github.com/assets/2434012/1843962/4a521bf0-74ee-11e3-802f-2d6ea6179de0.png)
after
![iss272-2](https://f.cloud.github.com/assets/2434012/1843963/4d1fa8de-74ee-11e3-97a8-3f1284741fec.png)