PHP-SDK is on packagist now: http://packagist.org/packages/facebook/php-sdk
If you use composer to install it, you no longer need to specify the facebook.class_file option.
Thanks for reminding me. I wrote about this specific package a while ago but never got around to implementing it here.
Consider it soon-to-be-done! :)
That should be it. Would you have a look and see if it looks good to you now?
Thanks! I submitted a PR with some suggestions.