Add Identity#getId():IdentityId.
Add ability to fetch single second factor.
Add ability to revoke second factors.
Optimise use statements.
Add undetected translation keys.
Merge branch 'develop' into feature/token-revocation

Conflicts:
	src/Surfnet/StepupMiddleware/ApiBundle/Controller/VerifiedSecondFactorController.php
	src/Surfnet/StepupMiddleware/ApiBundle/Resources/config/routing.yml
Suppress coupling between objects warnings for now.
Merge pull request #37 from SURFnet/feature/token-revocation

Add ability to revoke second factors