Adds margin to record callnumber browse display

![image](https://cloud.githubusercontent.com/assets/302258/3804808/6057a50c-1c2b-11e4-8de9-14eea71e2c8f.png)
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![image](https://cloud.githubusercontent.com/assets/302258/3804811/69a8f692-1c2b-11e4-8131-5b4b70af211c.png)