UC-33 collect user's gender from FB on signup

If a user signs up for a new Wikia account via Facebook, we want to make sure to collect their gender if it's available. During signup we now check with FB to see if they have a gender for the user and, if so, save it on our end.
I simply moved this method up above ```saveUserGender()``` so it would be closer to the order in which it's called.