Update 3.19.1

New: Billing and Delivery properties now available for export from orders.

Fix: Error when displaying delivery details in specific circumstances.

Fix: Directory titles were not displaying correctly when a parent directory specified.

Fix: Removed GUID output field from RSS feed as unnecessary and caused problems with import to Google Merchant Center.

Fix: Applied efficiencies to invoice and purchase order output.

Fix: Modified the discount pricing format to make it easier to customise.