Fix reference to Spree::Core::ControllerHelpers::Order
Bump selenium-webdriver gem version to support Firefox 15
Update for new admin redesign

Fixes #21
Use master spree
Correct unauthorized checks in specs
Remove useless new action definition inside UserSessionsController
Include correct ControllerHelpers sub-modules into user_registrations and user_passwords controllers
Don't restrict to just master branch
Require devise-encryptable in engine so main app doesn't have to add to Gemfile.

Fixes #46
Check if CheckoutController and OrdersController are defined before decorating them
Add ActionController::Metal decorator so that API has access to spree_current_user
Use root_path, not products_path, inside admin/_login_nav partial, as products_path may not always be around
We can no longer rely on backend controllers being present
Must include Spree::StoreHelper inside all auth controllers