Bug 971506 - [System2] Instantiable InternetSharing

https://bugzilla.mozilla.org/show_bug.cgi?id=971506

![screen shot 2014-05-11 at 3 31 57 pm](https://cloud.githubusercontent.com/assets/122602/2939828/1b16ef46-d95c-11e3-9102-da528ef898a0.png)