WooCommerce Order Status Manager 1.15.4

* Tweak - Cache order status posts within each request to prevent duplicate database queries
* Fix - Fix PHP notice when viewing trashed orders in WC 3.3+
* Fix - Re-establish argument parity with 'woocommerce_email_' actions

* Tweak - Improve icon picker UI: add Remove Icon button, match WordPress styles
* Tweak - Limit order status names to 35 characters
* Misc - Update FontAwesome to 4.7.0
* Misc - Add support for WooCommerce 3.3

* Tweak - Add order actions to manually send custom emails removed by WooCommerce 3.2
* Tweak - Don't suppress filters when getting statuses for improved WPML compatibility
* Misc - Remove WooCommerce 2.5 support