* New: added WordPress 4.9.8 compatibility
* New: added WooCommerce 3.5-RC compatibility
* New: updated Stripe API version to 2018-09-24
* New: updated plugin framework
* New: added pt_PT translation (thanks to Ricardo A.)
* Tweak: plugin now registers card even for subscription only orders;
* Tweak: set default card when processing subscriptions
* Tweak: removed create_function for php 7.2 compatibility
* Tweak: removed usage of deprecated WC function from gateway class
* Tweak: improved error handling for invoices: skip useless checks, and add notes to renew order, instead of parent one
* Fix: order total when paying from order-pay endpoint
* Fix: notices when registering a card
* Fix: check over subscription expiration date
* Fix: get_plan now does not create new plans any longer when just used to check plan existance (this mainly happens when checking if order has active subscription)
* Fix: SSL error notification on admin pages
* Fix: warning when failed attempts is not an array
* Dev: added yith_wcstripe_before_create_token trigger
* Dev: added yith_wcstripe_add_payment_method_result filter
* Dev: added yith_wcstripe_gateway_us_icons filter
* Dev: added yith_wcstripe_gateway_default_icons filter
* Dev: added yith_wcstripe_gateway_icon filter
* Dev: added yith_wcstripe_use_plugin_error_codes filter to show original API error messages
* Dev: added yith_wcstripe_error_message filter to let third party code filter error messages
