WooCommerce PDF Product Vouchers 3.12.3

* Fix - Prevent possible errors with other plugins due to type-hinting in add_meta_boxes hook
* Fix - Use correct voucher font cache path
* Fix - Prevent errors when viewing vouchers in older versions of PHP

* Fix - PHP errors for upgrade to 3.0 when voucher generation failed in previous versions

* Feature - Voucher template creation is vastly improved with a visual editor (no more painful scrolling!)
* Feature - View a list of generated vouchers to quickly see status and remaining value
* Feature - Easily search voucher list for voucher number to quickly add customer redemptions
* Feature - Add voucher redemption directly from voucher list actions for fast management
* Feature - Manually generate a voucher for a customer from your store admin
* Feature - Improved voucher number generation for increased security
* Feature - Supports partial / multiple redemptions for vouchers
* Feature - Ability to void remaining voucher value
* Feature - Now supports non-ASCII characters (e.g., Cyrillic) for PDF generation
* Tweak - Now includes 6 default voucher designs! Choose one or add your own.
* Fix - Recipient email field uses proper HTML field type
* Fix - Selected variation attributes will now be shown as part of the product name
* Misc - Add copious for-developer improvements: new hooks, more extensible structure
* Misc - Refactored for several other minor fixes and improvements
* Misc - Added support for WooCommerce 3.0
* Misc - Removed support for WooCommerce 2.4.x and 2.5.x