Prettify Market Gem

Adds a margin to the purchasable Gem in the Market so it doesn't look so wonky compared to other market items.

Before:
![image](https://cloud.githubusercontent.com/assets/4501321/5293662/be3c8416-7b3b-11e4-8b1b-27be4329bf34.png)

After:
![image](https://cloud.githubusercontent.com/assets/4501321/5293668/d7547e72-7b3b-11e4-83e1-96faf477bebb.png)

I couldn't find anywhere else this particular zoom level of the Gem icon was used, but keep an eye out!