fixes date display on customer list page
fixed docblock for WC_Product::get_children(), closes #4664
fixed the indentation in includes/abstracts/abstract-wc-product.php file
fixed some coding standards in includes/abstracts/abstract-wc-product.php
removed unused global vars in WC_Report_Coupon_Usage::output_report, closes #4665
fixed docblock for WC_API_Customers::query_customers, closes #4666
fixed docblock for WC_Order::get_formatted_line_subtotal, closes #4667
fixed the indentation in includes/class-wc-order.php
fixed some coding standards in includes/class-wc-order.php
updated the WC_Order version to 2.1.0
fixed docblock for meta_is_product_attribute() function, closes #4668
fixed the indentation in includes/wc-conditional-functions.php
fixed undefined username variable in myaccount register using registration generate username as true
fixed the indentation in includes/class-wc-form-handler.php
fixed some coding standards in includes/class-wc-form-handler.php
$tax_code was url encoded , so decode it.

I can't read tax code at this box, if used Japanese in tax code. I want to read it in Japanese, so decode here.
Update readme.txt
Fix completing order payment for deleted product

When marking payment as complete on an order which contains a product which has
since been deleted, a fatal error will be thrown because the product is assumed
to exist.

The specific error is `PHP Fatal error: Call to a member function is_downloadable()`.
It occurs when checking if the order status should be set as completed or processing,
by determining if the product on the order is downloadable and virtual.

This patch will mark an order as "processing" if the product has since been deleted.
removed deprecated function
improved the deprecated woocommerce_placeholder_img function, closes #4684