WooCommerce Mix and Match Products 2.7.0

* NOTICE: Add to cart script heavily refactored. If extending, please test integrations in staging environment before updating.
* New: Support a percentage container discount when in per-item pricing mode.
* New: Ability to edit a container's configruation from the cart.
* New: WooCommerce Print Invoices & Packing Lists compatibility.
* New: Scripts support handling of price suffix with front-end calculation of taxes.
* New: Filter woocommerce_mnm_child_quantity_input_args to change args for only Mix and Matched item quantity selector.
* Fix: Order Again support for WooCommerce 3.5 .
* Fix: Add discount, layout, form location fields to import/export.
* Fix: Handling of Mix and Match content data during import/export.
* Fix: Incorrect price strings in certain instances
* Tweak: Vertical alignment of quantity inputs

* Fix: Fatal error with Product Addons 3.0, insufficient arguments passed to woocommerce_add_cart_item_data
* Fix: Fatal call to undefined method error on product save when updating constant is defined.
* Fix: Hide reset link when item has not been configured

* New: Cache calculated prices at runtime
* New: Add content in WP Privacy Policy Guide
* Fix: Replace deprecated WC()->cart->get_cart_url()
* Fix: Explicitly declare grid style inputs as block elements for theme's that don't
* Fix: Add missing parameters to 'woocommerce_get_price_suffix' filter
* Fix: Mobile cart styles
* Tweak: Change thumbnail size to woocommerce_thumbnail.