Woocommerce Payment Gateway Based Fees 5.2

* Change WC_Order to WC_Abstract_Order as type in function definintion
* Replace new WC_Order by wc_get_order()

* Modified bugfix subscription plugin - remove our fees from existing order on renewal and manual payment see github.com
* EU VAT plugin temporary fix: does not take care of is_vat_exempt of a saved order (see classes\class-wc-order-add-fees.php)
* WC 3.0 compatibility adjustments

* Bugfix subscription plugin pay for order page - adds all fees from existing order (we do not recognise our fees any longer)