facebook sdk upgrade @ 16d696c138

* Added the extra param: appsecret_proof to the oauth api calls
* Fixed a vulnerability with signed requests
* clarified apache specific lookup for ssl & added ability to loo
* Avoid trying to reuse spent authorization codes
* Use `empty()` for signed request value check
* bump version to 3.2.1
* fix broken tests and remove some broken ones
* updated cert bundle to use the current curl bundle