publish DID_LOGIN event

Summary: Publish a DID_LOGIN event that includes the response from the authentication request.
Details: This will allow apps to react to the login event and configure stripes/session/localForage/etc with app-specific details. This will allow us to remove logic related to non-core modules (e.g. service-points) from stripes-core, which should only have knowledge of interfaces provided in the minimal platform (users, authtoken, permissions, login, configuration).