add missing model translation.

Fixes #4410
Dont restart checkout_flow for completed orders

No need to destroy all shipments or set order back to first checkout
state. Currently shipments for completed orders are managed by
OrderInventory#veriry

Conflicts:
	core/spec/models/spree/order_spec.rb
Fix duplication of spree option values when product is cloned

Fixes #4420
Fixes #4417
Bump to 2.1.5
Bump to 2.1.6.beta
[api] Attempt authorization for an order if an order token is passed

This stops the 'You must specify an API key' error message from (incorrectly) appearing. That message is now supressed if an order token is passed in.

When an order token is passed, the authorize_for_order filter is called, which attempts to find an order and then compares the order's token with the order token from params/headers

Conflicts:
	api/app/controllers/spree/api/base_controller.rb
Remove stray jbuilder file
add missing translation
avoid unnecessary database updates
update shipment state if it didn't change
Remove overriden files
Fix shipping_method factory
Fix order -> line_items associations
Save tax_total when saving order
Move file to dotandbo-spree repo, line_items fixes

* Allow an admin to set a line item price or estimated shipping date
* Don't set the line_item price until checkout