is_in_stock uses notify_no_stock_amount option. Closes #3446.
Allow access to admin-post Closes #3814
Fix variation saving and notices
Prevent variable products without variations from being posted and show error in admin. Closes #3763
Filterable get_base_postcode and _city methods used for base taxes. Closes #3810
woocommerce.php PHPDoc cleanup: correct @returns and @deprecated markup