Have the remove_taxes() method set subtotal to subtotal_ex_tax

As committed on master branch:
- https://github.com/woothemes/woocommerce/commit/742cd3ae364243bdd4e2108d0c10a3458f4893f9
Allow layered nav to work with non pa_ prepended taxonomies

As committed on master branch:
- https://github.com/woothemes/woocommerce/commit/f49bd2cd771d6de3a349a2c882b40c65b56f8eba
Better backwards compatibility with _woocommerce_exclude_image

As committed on master branch:
- https://github.com/woothemes/woocommerce/commit/59db08d70bb3f3f292c5d49e132179ed891f251d