Wrong REQUEST_PROFILE constant for Facebook API v2.4

[ArniPL]

Hello.

I found an issue with REQUEST_PROFILE constant in /src/OAuth/UserData/Extractor/Facebook.php.

Since Facebook changed things in API v2.4, requests using that constant no longer retrieve full profile. Only name and id fields. So now we have to explicitly requests needed fields.

To get things to work, I changed this line to:

const REQUEST_PROFILE = '/me?fields=id,email,first_name,gender,last_name,link,locale,name,timezone,updated_time,verified';

I'd make a pull request but I don't know if this is correct way of handling this.