RSpec 3.1 support & Fix a couple Rails 4.1.6 regressions.

Conflicts:
	api/spec/controllers/spree/api/base_controller_spec.rb
	api/spec/controllers/spree/api/promotion_application_spec.rb
	api/spec/controllers/spree/api/promotions_controller_spec.rb
	common_spree_dependencies.rb
	core/spec/lib/spree/core/controller_helpers/search_spec.rb
	core/spec/lib/spree/core/controller_helpers/store_spec.rb
	core/spec/lib/spree/core/controller_helpers/strong_parameters_spec.rb
	core/spec/models/spree/customer_return_spec.rb
	core/spec/models/spree/order/checkout_spec.rb
	core/spec/models/spree/order/payment_spec.rb
	core/spec/models/spree/order_spec.rb
	core/spec/models/spree/promotion/actions/free_shipping_spec.rb
	core/spec/models/spree/promotion_spec.rb
	core/spec/models/spree/reimbursement/reimbursement_type_validator_spec.rb
	core/spec/models/spree/reimbursement_type/credit_spec.rb
	core/spec/models/spree/reimbursement_type/original_payment_spec.rb
	core/spec/models/spree/return_item/default_eligibility_validator_spec.rb
	core/spec/models/spree/return_item_spec.rb
require at least one valid payment on transition to complete
Fixes #5350
Add scoping when matching to orders tax_zone to find possible relevant zones
Ensure default tax zone