WooCommerce Customer Order XML Export Suite 2.6.3

* Feature - Use a batch-processing fallback for manual exports on incompatible hosting environments
* Fix - Ensure that auto-exports will not allow more than one export job to be created at a time
* Fix - An issue with exports remaining queued due to a nonce check incorrectly failing
* Fix - Allow the products auto-export setting to be cleared
* Misc - Remove support for WooCommerce 2.5
* Dev - Add `manage_woocommerce_xml_exports` capabilities for viewing and managing exports

* Tweak - Support full billing and shipping name in custom customer export formats
* Fix - Line item meta was not being consistently output in WooCommerce 3.1.x

* Fix - Deprecation warnings in WooCommerce 3.1