WooCommerce Moneris Gateway 3.4.0

* Tweak - Save the last four digits of a payment method to order meta when using Hosted Tokenization
* Fix - Ensure credit card CSC values are sent to Moneris in all cases when using Hosted Tokenization

* Fix - Address transaction errors which can occur when orders contain products with HTML tags in the title
* Misc - Add support for WooCommerce 3.8

* Feature - Add support for Apple Pay
* Tweak - Allow filtering the API request data
* Dev - Refactor the API to extend the SkyVerge Plugin Framework
* Dev - Update the SkyVerge Plugin Framework to use namespaces and move it to the /vendor directory
* Misc - Remove support for WooCommerce 2.6
* Misc - Require PHP 5.6+