Payment tokens was introduced in 2.6 and was updated to use the new CRUD code while some of the CRUD system was still in flux.
While most things were correct, the prop handling for custom fields (like a card's last 4 digits) were directly calling meta functions, instead of delegating to the data store/parent.
This PR moves these props to `extra_data` and follows the same pattern as product types or order items. It also updates some version tags to 3.0.0. Finally, it adds an additional test for saving meta after a create which looks like it was lacking.
To Test:
* Run `phpunit`.
* Go to the "My Account" tab and add a new payment method. You need a payment gateway that supports this, like Simplify.
* Test the add a payment method flow.
* Make a test purchase using the saved payment method.
Also makes sure to properly unset other tokens when a new one is set as default. Finally, we make sure that a user is always set in our payment token tests (which was broken in some WP versions which alerted us to some broken tests).
* Remove $token_id parameter from WC_Order's add_payment_token. get_id() can be used to access the ID
* Rename our list of token ids from meta to $token_ids as it makes more sense
* Cleaned up/fixed some of the comments in WC_Payment_Token
* Some code formatting fixes
Justin Shreve
Claudio Sanches
Mike Jolley
Claudio Sanches
Aristeides Stathopoulos
Scrutinizer Auto-Fixer
Joey Kudish