Add a default format if no format is defined in the locale file. Use the same default format as the datepicker gets in the translations partial.

Fixes #3602
While an order_id field exists within inventory_units, we should be able to retrieve these using an association

Fixes #3744
Add regression test for #3744
Associate user in Order `merge!` when possible

Users might be losing their cart changes when they come back but don't
visit either the /cart page or the /checkout

Fixes #3742
Fixes #3736
Fix path to cart.png

Fixes #3747
Bump active merchant to 1.38.1

Fixes #3745
refactored spree stock estimator

Extracted functionality out of #shipping_rates for choosing the default
shipping rate and the for the order shipping rates should be sorted in,
in the interest of overriding said behavior.

Change-Id: Iefcce00f1f2ebfedd565dd3aeb540a6111ffc5b7

Fixes #3748
Fix product paging issue

Fixes #2851
Fixes #3064

Conflicts:
	frontend/app/controllers/spree/taxons_controller.rb
Fix expectations in order/adjustments_spec so that it now passes
[Fixes #3770] Use 2-1-stable branch of spree_auth_devise when generating sandbox
Assign location to shipment when importing orders (api)
Should have ability to ensure confirm step is always in progress bar.
Update credit card factory to work any year.
Fix Order#confirmation_required? spec.
Use Time.now.year as Date.year is invalid.
fix page action buttons line wrap in admin
Refactors after_cancel to allow the Mailer method to follow the pattern set in other models.

Allows OrderMailer.cancel_email be sent asynchronously with delayed_job#handel_aynchronously

Fixes #3759
Move spree/shared/address partial into frontend

That's the only place Spree uses it

Related to #3758
Clean up backend address forms

Related to #3758
Introduce Order shipping_eq_billing_address method

This might help both frontend and backend to figure out whether the
use_billing checkbox on address forms should be checked. API users
should benefit of it as well

Related to #3758