Create woocommerce-uk_UA.po

Ukrainian language
Take out default variations #3169
Only load integration abstract when needed #3169
Class name consistency for woocommerce_attributes > product_attributes. See #4019
Fix markup on form-pay.php

Payment method fields were not displaying on the "Checkout -> Pay" page
because checkout.js was using a input#payment_method_{name} selector, which
worked fine with the payment method markup used in the review-order.php template,
but not with the markup used in the form-pay.php template.

This moves the #payment_method_{name} attribute from the <li/> elements to the
<input/> element so that checkout.js correctly display's payment method fields.
We'll let autoload handle this file loading

Revert: 1428bf8f9c8f9f876263386ada695375c6fc8d7d
Fix use of __CLASS__ when not in class
Merge pull request #4049 from thenbrent/fix_deprecated_class

Fix use of `__CLASS__` when not in class
Add WP JSON API Library
Fix strict standards warning
Add a custom trigger handler based on the value of select#field_to_edit
Modify WP_JSON_Server to allow authentication
Add required global functions for WP_JSON_Server class
Add REST API settings stub
Remove unused WP_JSON_Posts class
Add REST API endpoints/methods to WC API class
Add new /checkout/add-payment-method/ endpoint

Part of #3396
Add add_payment_method_action() handler

Part of #3396
Add form-add-payment-method.php
Fix up markup on form-add-payment-method.php

So that checkout.js correctly displays payment method's fields.
Part of #3396