Refactor Spree::Shipment:

* ruby19 hash syntax
* More DRY
Refactor Spree::Activator
Refactor Spree::Adjustment
Refactor Spree::Alert
Refactor Spree::BillingIntegration
Revert "Fix ambiguous column name in UpdateShipmentStateForCanceledOrders"

This reverts commit 0c04aade284df9eb06adee5fb6fb3b9db5d4f43a.

rake test_app was getting SQLite3::SQLException: near ".": syntax error
Refactor coupon applicator
Revert "Refactor lambda to -> notation"

This reverts commit 6cfd0144f466432f22675be16349d728bf993bb0.

Conflicts:
	core/app/models/spree/shipment.rb
	core/app/models/spree/zone.rb
Refactor Spree::Calculator and Spree::Classification
Refactor Spree::Country
Add missing argument to manifest_unstock method call
Refactor Spree::CreditCard:

* ruby19 hash syntax
* Use state_machine helper for checking payment state
* Remove #first_name? and #last_name? because AR already define these methods
* Rewrite the test
Refactor Spree::Order - using -> notation for lambda
Validate presence of variant on StockItem
StockItem#determine_backorder isn't being used, removing it and it's spec.
Refactored Spree::Core::CalculatedAdjustments#calculators
Require Shipping Calculators to Inherit from Spree::Calculator::Shipping
Remove call to Order#remove_variant, deprecate method
Deprecating Order#add_variant
[core] Refactor Spree::LineItem