WooCommerce Customer Order Coupon CSV Import Suite 3.12.3

* Fix - Ensure order currency and customer user are properly set via import

* Fix - Address a potential fatal error with imported jobs being removed from the queue when over 14 days old

* Tweak - Use direct SQL queries for background jobs to prevent caching issues on certain hosts
* Tweak - Use GET request to dispatch background jobs as a workaround to POST request rate-limiting issues on certain hosts
* Fix - Order data could be missing in some cases while creating orders with WooCommerce 3.0+
* Fix - Ensure refund dates use the proper format in WooCommerce 3.0+