Fix bug where polyfills file fails to included properly when using th…

…e built-in auto loader

Bump Graph API version to v2.7

- Fix notice that is raised in `FacebookUrlDetectionHandler` (faceboo…

…karchive#626)

- Fix bug in `FacebookRedirectLoginHelper::getLoginUrl()` where the CSRF token gets overwritten in certain scenarios (facebookarchive#613)
- Fix bug with polyfills not getting loaded when installing the Facebook PHP SDK the manual way (facebookarchive#599)

Bump Graph version to v2.6; add new Birthday class; add better error …

…checking for app IDs

Remove mbstring extension dependency

Updated to 5.1.4

updating to 5.1.3

Updating to 5.1.2

Updating to 5.1.1

Updating to 5.1