Add spec to ensure canceling + resuming an order works
completed? should return true if state == 'complete' too

Conflicts:
	core/app/models/spree/order.rb
Disable acts_as_paranoid for StockItem if deleted_at column does not exist

This would not exist in the case of a migration from 1-3-stable to 2-0-stable.

Fixes #3805
change message to selected_quantity_not_available when selected quantity can not be supplied