Merge promo into core+frontend
Support money 5.1.0
[frontend] Remove useless comments in Admin::OverviewController
[frontend] use correct flash messages in Admin::ProductsController
Re-add RespondWith module
Remove money dependency from frontend

This exists in core, so no need to have it here
[frontend] Remove display heading check in spec/requests/admin/configuration/payment_methods_spec.rb
Adding Order#variants

Convenience method for grabbing a list of variants

Fixes #2195
Set flash[:success] correctly in Admin::ProductsController
Remove require for spree/core/responder and store_helper in frontend.rb
Re-add db/default folder

Thanks to voondo for pointing this out.
Re-add core/db/seeds.rb
Add Spree::Core::ControllerHelpers which can be included to include all its submodules
Use API for variant searching on new order form
Use API for taxon autocomplete
[api] Fix taxons controller tests
Use versioncake for versioning of API resources

Fixes #2209

* Unversion zones controller so it can be used with Versioncake for testing purposes
* Zones controller using versioncake for versioning
* Move other controllers so they make use of Versioncake
* Rename all views to make use of Versioncake
* No v2 of api yet

Conflicts:

	api/app/controllers/spree/api/v1/base_controller.rb
	api/app/controllers/spree/api/v1/taxonomies_controller.rb
	api/app/controllers/spree/api/v1/taxons_controller.rb
	api/app/views/spree/api/products/index.v1.rabl
	api/config/routes.rb
	api/spree_api.gemspec
[frontend] No need for cleanTaxons method in taxon_autocomplete

This is due to child-root removal in the API
[core] Re-add missing script directory
Re-add respond_to :json call to Api::BaseController