Handle edge-case in rounding of shipping costs

Fix changes in checkout API, add safety measure in certain situations for "cancel remaining".

Fix bugs in handling aborted express transactions; handle coupons with shipping correctly.

Fix checkout widgets on mobile and phone numbers being stripped when using external payment methods in checkout

Improve MobilePay buttons for express, fix banners

Support new express checkout for Vipps + MobilePay, remove support for ecom.

Minor bugfixes

Support for All Products for Woo Subscriptions in Checkout

More places in the code where a cost could be an empty string fixed.

Woo 9.x seems to return tax/cost for certain free shipping methods as an empty string instead of zero or "0". This causes type errors on newer php versions when one tries to add tax + cost. This version contains workarounds for this.