Adding Category & Tag Classes to Product Page

By default will add category & tag classes to their article tags for generic posts. We should do the same with our products. This will add more flexibility for styling.

![bilbos_ring___woocommerce_github](https://f.cloud.github.com/assets/1065372/1211691/8322e516-260d-11e3-90b4-e06c4331a673.png)

Reference: https://woothemes.zendesk.com/agent/#/tickets/101838