Update class-wc-post-types.php

This for each slows Woocommerce down because of making all taxonomys. I've got a webshop with 33,000 products and thousands of attributes, with a server load time of 6 seconds. I've recodes this area to only load taxonomys when needed. Like when viewing the Attribute page or a category. Woocommerce is perfect for webshops, only bug is this thing. http://koophetzelf.nl.