[api] Add eager loading for stock items, products, images and prices to variants#index
Dont update shipments and payment in order cart

Adding a product to cart on a fresh spree install currently runs 41 SQL
queries. This change makes the POST orders/populate request run 34 SQL
queries.

So each time the store needs to run `order.update!` and the order is not
completed yet we run 7 less queries. That could make a big difference
when lots of promotions are involved.

Fixes #3513
Drop spree_mail_methods table

It's no longer used since Spree 2.0

Fixes #3511
[backend] Add _spec suffix to stock_transfer test
Refactor and add test to Spree::Payment#set_unique_identifier.

Fixes #3493
Bump aws-sdk

Should be pretty safe, and this allows use of newer AWS services.

Change-Id: I24b4a006409f202138699d63285eee508fe86c4b

Fixes #3514
Use includes(:model) in promotion_credit_exists? check for fewer queries

Fixes #3517
override permalink of deleted product for creating new product of same name without errors
override permalink of deleted product updated test

Fixes #3471
Fix breakages with stock_transfer_spec

These have existed for a while, they've just not been run because the file was named incorrectly
Check if billing_address is present, not if the order is in a specific state, when checking if a user can view the payments for an order
Provide id for admin/payments/_form
[backend] Correct transalation oin admin/payments/show
[backend] Display currency symbol next to price on payments/show
Updated version to return 2.0.5.beta

Fixes #3528
Set bill_address to nil to fix failing payments_controller_spec test

The test in the controller now checks whether or not this association is nil, rather than doing a state check
[backend] Make 'Mail Methods' link highlight as the active link when at mail_methods/edit

Fixes #2961
properly encapsulate Spree::Payment::Processing module

Fixes #3523
Reduced nested conditional to compound expression

Fixes #3527
Add internal name for stock locations.

Includes light refactoring of stock_locations/index.html.erb from Ryan Bigg.

Fixes #3532