[api] Added a CheckoutsController
- Allows creation of a new, empty order
- Can transition an order from cart to complete state
- Removed now unneeded address and delivery actions from API's
  OrdersController
[api] Added support for updating an order's payments using CheckoutsController
Reject instead of deleting months from the localization list

The %B date formatting operator relies on nil for the first month
in the month_names array. Deleting it from I18n will cause month
shifting

Fixes #2427
Correction of the problem that a newline is added to by google chrome browser

Fixes #2447
sort en.yml

Fixes #2446
Correct factory used in product_attributes for shared "product prototype" context

Fixes broken build: https://travis-ci.org/spree/spree/jobs/4244803
Cleanup product and variant factories

Fixes #2419
Freeze to jquery-rails 2.1.4 as jQuery 1.9 breaks a plugin
Refactor address_row fields
[core] Hides shipping address form if Use Billing Address checkbox is checked [admin]

[Fixes #2456]
Refactor spaces in syntax
[api] Return relative attachment url for product images
correction translation missing

Fixes #2463
edited admin/shipping_methods.js to be more explicit when manipulating checkbox inputs so that additional checkboxes are not affected

Fixes #2465
Don't change Property's presentation name if it's already set

Fixes #2455
Removes adjustments from incomplete orders

Every time a promotion is removed its adjustments should be removed from
incomplete orders

fixes #1046

fixes #2453
Adding adjustments to Orders Show

Fixes #2449
Adding Credit Cards to API

Fixes #2449
Remove guard dependencies
Add a test for adjustments + credit_cards

Related to #2449