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
Correct factory used in product_attributes for shared "product prototype" context

Fixes broken build: https://travis-ci.org/spree/spree/jobs/4244803
Freeze to jquery-rails 2.1.4 as jQuery 1.9 breaks a plugin
[api] Return relative attachment url for product images
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
make sandbox shell script more resilient
correctly show variant options

Fixes #2466
Reset preferences after spec to properly teardown test and avoid files being saved where they are not gitignored.

Fixes #2467
Use pluck instead of mapping attributes for performance.

Fixes #2468
An order should be able to ship when awaiting return and in the returned state

Fixes #2444
including Spree::Core::ControllerHelpers will now include all sub-modules
refactor preferences reset for specs (reduced core test from 9 min to 5 min)
Stringify api_key

By default there is no api key generated. I just managed to break into api on test installation using `?token[]`, one of my favourite CVEs
@radar, please take a look at Mr. Outsider's PR

Fixes #2492
tidy up spree preferences testing support
[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
move rabl configure into after_initilize block to fix rails generator
error