attr_accessible :country_id is duplicated

[Fixes #3114]
Make sure that the images aren't CMYK. [Fixes #3104]
No need to pass option on spree.promo initializer

For some reason this was making the calculator.shipping_methods nil in
the spree app initializer. It prevented users from adding their own
calculators with code like:

  Rails.application.config.spree.calculators.shipping_methods << CustomUserClass

Fixes #3118
Deprecate Order#shipment as split_shipments makes it less relevant
Stop using deprecated Order#shipment method in OrderInventory spec
Remove nonsense js code on backend customer details

When picking up a user at the backend customer details order step that
code would empty all address fields, including the previously set
default country

This should fix the backend build.

Fixes #3129
Scope shipping rates as per display_on [Fixes #3124]

As shipping method rates set to appear only in backend should not be
displayed in frontend as well

[Fixes #3119]
Add nil object check for StockLocation#fill_status [Fixes #3131]
Fix product property delete url.

Fixes #3120 #3123