Adding beta option to FB library.

Pull request for #14. Very old, but easy enough to implement.
When beta option is present, paths will be graph.beta.facebook or api.beta.facebook.
Fixing a couple of non-working tests.
Adding test file for options, only testing new beta option.

Also, I noticed that line 250 in the fb.js is a condition that is always true. I thought of just setting the variable to true, but I wasn't sure if that was the intention or not.