WooCommerce Shipping Multiple Addresses 4.2.5

* Fix - Should check if there are valid states for the country before validating the field.

* Fix - Free Shipping coupon with minimum spend not working as expected.
* Tweak - WC 4.1 compatibility.

* Fix - Postal codes with format 0000 AA are not recognized.
* Fix - When there's specific country restrictions, SMA does not abide to restrictions for state/provice.