Fulfillment por Amazon (MCF) para WooCommerce 4.2.9.8

* Fix: Do not send products without an SKU. This is to prevent errors in submission
* Fix: Check status response of orders sent to fulfilment to prevent marking orders as sent when it failed.

* Bug fixes

* Fix issues with manually sent orders in the admin for products not meant to fulfil with Amazon

* Tracking code fixes and order checks
* Better logging

* Connection url updates.
* Code fixes and improvements.

* PHP 7 compatibility fix.
* Other code fixes and improvements.

* Add integration with Shipment Tracking plugin.
* Only show tracking order notes once when syncing the order status.

Fix order sync tracking details.

* Improved option settings usage

* Fix issues with shipping cost calculations.
* Add logging for shipping calculation errors.