Add display name for Studio Advanced Component menu

Studio uses the `display_name` field default for the list of "Advanced Components".

![image](https://f.cloud.github.com/assets/2948394/2432827/2051eeb4-ad76-11e3-8a1b-0ed4e9474dc7.png)

This field is also used by the LMS for the "tool tip" in the horizontal nav:
![image](https://f.cloud.github.com/assets/2948394/2432839/c1c52d74-ad76-11e3-8166-49755c2eb26b.png)

I'm not sure whether `display_name` should be configurable from the XML or not, but this at least uses the correct terminology in the Advanced Components menu.