Put studio Share button on top line when no arrow buttons

- Fix alignment of Studio arrow buttons

## Before

![image](https://cloud.githubusercontent.com/assets/206973/3818135/a9d15c42-1cde-11e4-8184-d6ed968b2563.png)

![image](https://cloud.githubusercontent.com/assets/206973/3818124/98ea3322-1cde-11e4-986c-0ca66ed4bc5e.png)

## After

![image](https://cloud.githubusercontent.com/assets/206973/3818129/a2f5c17e-1cde-11e4-8cf8-3d06d1c318d3.png)

![image](https://cloud.githubusercontent.com/assets/206973/3818121/91bf2116-1cde-11e4-87e7-7ba8f2780ddb.png)