WooCommerce Social Login 2.16.0

* Misc - Add support for WooCommerce 3.7
* Misc - Remove support for WooCommerce 2.6
* Misc - Require PHP 5.6+

* Fix - Address an issue with Facebook or Google login affecting some installations
* Misc - Use Facebook Graph API v2.12

* Tweak - Add support for LinkedIn API v2
* Fix - Handle properly OAuth requests errors
* Fix - Add missing options key for WPML translation
* Fix - Do not display admin notices for lack of SSL support on newer WooCommerce versions running on HTTPS
* Dev - Filter the callback URL format
* Misc - Upgrade HybridAuth authentication library to v2.14.0