The Events Calendar - Event Tickets Plus 6.3.0

* Feature - Add QR API settings field and button to generate key [102116]
* Feature - Add base REST API system and endpoint for QR check in [102107]
* Feature - Add security code and REST path to QR code url and require use of security code for REST check in [102112]
* Fix - When adding a WooCommerce ticket to the cart, redirect only if the "WooCommerce" setting is set. Thanks to Thomas and Ilkka for flagging this! [46648]
* Fix - Display unavailability message when tickets are not yet or no longer available [81334]
* Tweak - Add `tribe_tickets_plus_trash_ticket` filter to give the opportunity to trash tickets when deleted instead of actually deleting them [46393]

* Fix - Fixed an issue with new "Enable QR codes for tickets?" option being only visible if WooCommerce was active [107236]
* Language - 2 new strings added, 1 updated, 0 fuzzied, and 0 obsoleted

* Tweak - Make QR codes optional via new "Enable QR codes for tickets?" option in Tickets settings [41649]
* Fix - Remove attendees from the public list if their order have failed (Thanks @beerddwr for flagging this!) [103912]
* Fix - Fixed an issue where EDD was throwing insufficient stock error for shared capacity tickets (props to @artstream8401 for reporting this!) [101079]
* Fix - Clean the attendees cache every time an order is updated, so the changes are reflected immediately (Thanks @bartenderatlas, @artistinformatici, @danceworks and others for reporting) [103831]
* Fix - Synchronize the event cost when a WooCommerce sale start or end (Thanks @floydcountrystore for notifying us!) [104019]
* Fix - Ensured that the tickets start and end sale date respect the event timezone (props @Ryan, @Georges and others for flagging this!) [76683]
* Fix - Add class to handle WooCommerce order refunds on a ticket basis [102081]
* Fix - Prevent the event tickets page to break when EDD is deactivated and there were EDD orders [64253]
* Fix - Add default title to the ticket field set if none provided [70739]
* Fix - Sanitize HTML classes for ticket attendee details in the admin area (Thanks @Gergana, @ucheng and @mr-d for flagging this!) [65385]
* Fix - Ignore whitespaces in ticket required fields (props @jonahgirl and @seanaguilar for notifying us!) [95950]
* Fix - Render ticket fields without label (Thanks @creeert-net and @daviddweb for spotting this) [63286]
* Tweak - Made the QR code base URL default to having a trailing slash to prevent issues with some server configurations [74797]
* Tweak - Added new `tribe_tickets_qr_code_base_url` to allow easy filtering of the QR code base URL [74797]
* Language - 5 new strings added, 74 updated, 0 fuzzied, and 1 obsoleted