Fix potential error if variation doesn't exist
[2.2] Fix refund date.

Fixes #6499
$cart_totals should be checked to see if its an array

Closes #6496
Register post types before each unit test

Fixes #6501

see
https://core.trac.wordpress.org/changeset/29860/trunk/tests/phpunit/incl
udes/testcase.php, apparently we were #doingitwrong  🙈
Prevented warnings when countries is empty in shipping methods.

Stopped this erros:

PHP Warning:  array_intersect(): Argument #1 is not an array in
wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-shipping-method.php
on line 182
PHP Warning:  in_array() expects parameter 2 to be array, null given in
wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-shipping-method.php
on line 194

@mikejolley
Prevent warnings in WC_Shipping_Method::is_available() when exclude countries
In the US address format, use state code rather than the full state name.
[2.2] Prevent notice if meta is not set Closes #6514
Use mb_strtolower to prevent issues with unicode chars

Fixes #6525
Make cart total consider taxes

Fixes #6522
[2.2] Fix /shop/ base URL Non Latin issue with url decode

Fixes #6512
Fix conflict
Turn caching back on
Fix grunt file conflict
Check mb_strtolower exists.
Only show integrations subnav when there are multiple integrations.
Coupon API: Don't return current timestamp when expiry_date is not set

Fixes #6546
wc_update_product_stock should update stock regardless, if the meta data doesn't currently exist

Fixes #6553
Allow for non-integer stock quantities

It looks like a3b522aff87dc89c37dd4b6bbb85a9b208ffe15a removed this
ability.
This would be very useful for extensions like Measurement Price
Calculator.
Update class-wc-addons-gateway-simplify-commerce.php

Use new $order->get_status() in lieu of legacy $order->status to support the new post_status format in WC 2.2