allow for freeplay without sharing

![image](https://cloud.githubusercontent.com/assets/1767466/5175010/430ec9d6-73eb-11e4-8da8-9c26f1ccff54.png)

I don't love that the field is disableSharing instead of enableSharing, but the default case is that we want to have sharing work for freePlay unless disableSharing is set.