Remove open_id_authentication and restful_authentication plugins
[gem] Add omniauth-openid
Remove AuthenticatedSystem, add simplified methods

Simplified authentication-related helper methods added to
ApplicationController replace old boilerplate in AuthenticatedSystem.
Fix AuthenticatedTestHelper and move into spec/support
Whitespace cleanup
[migration] Add Authentications
Configure OmniAuth to use OpenID
Reset the session when the current user has been deleted
Fix User#fullname= to work with single-word names
Add AuthenticationsController

Handling sign in/out, soon to handle authentication management
Extract default path used after signing in/out
Remove BrowserSessionsController, update routes
Rename login_required filter to authentication_required
Improve wording of authentication flash messages

login => sign in
[migration] Create OpenID authentications from existing users
[migration] Remove auth-related fields and methods from User
Stub user_profiles? in view specs
Fix AuthenticationSpec: Use OmniAuth::AuthHash, not Hash
Fix UsersController#destroy spec

It wasn't logged in as any user when attempting to test mortal behavior
Fix flash bucket names in selector votes controller spec