Makes validator on Spree::Product#permalink tenant aware
Upgrades spree 1.3.0 => 1.3.1

Also reorders dependencies in the Gemfile that used by the spec/dummy
test app.
Enures that model columns update before running db:seed
Deletes product data before running empty store examples
Adds spree_auth_devise for tenant user support

* Makes validator on Spree::User#email tenant aware
* Removes uniqueness database constraint on Spree::User#email
* Updates specs that need to access admin interface
* Ensures that app generated by test_app uses Spree::User

Note :This couples spree_landlord with spree_auth_devise and thus
devise. This support can be moved into it's own gem later, if needed,
but we're keeping it in here for now.
Adds support for tenanted user accounts
Improves tenant creation rake task

* Fake short names and domain names provided by the ffaker gem
* Adds the ability to generate sample products
Adds initial super admin support
Adds suport for toggling super admin through backend

* Also corrects the location of the `normal_admin_users_spec` and the
`super_admin_users_spec`. These were living in `spec/api`, but they
were using Capybara, so they've been moved to `spec/features`.
Adds additional security for super admins
Wraps up super admin support

* The first admin created is a super admin
* Regular admin users are not show edit or delete links for super
  admin users
Adds support for a super admin that can manage all tenants

* The first user that's created will be a super admin
* Super admin users are able to create new users as super admin
  and to promote other admin users to super admin
* Each super admin user can log into every tenant
* Normal admins are tenanted just like non-admin accounts
Merge branch 'master' into topic/tenant-assets