Documentation about migrating away from Gradle-based projects.

Some screenshots too.

![image](https://f.cloud.github.com/assets/326857/1445499/431196bc-4222-11e3-8f80-bbc3bb3afe73.png)

Regarding the FB developer alert, look for the tiny yellow bar at the top of https://developers.facebook.com/apps

See https://github.com/rogerhu/Tahoe/blob/8eda9a7f05fdbd3a898d9c39071f16396bd7660d/README.md