Feature/use facebook sdk properly

Does not change anything to the .ane file

The facebook ios sdk as a submodule needs to be both checkout to the correct version and recompile each time. And after updates, its possible that even if the facebook sdk is at the correct version, the .framework used during the compilation has not been updated (because you need to recompile the whole sdk after checking out to it).
For further updates, the .framework can be downloaded directly from the facebook website