Fix: date width

Before:
![SilverStripe Artikelen](https://f.cloud.github.com/assets/1517053/128907/445c587e-6fcb-11e2-857c-2b50959bc466.png)

After:
![After](http://i.imgur.com/o0FQt10.png)

Fix for b350ded87ce6309733f32c0f04d4b5b61483200f