- Remove SetUsername itself, and add a username parameter to DeviceClaim,
ListEnrolledFingers and DeleteEnrolledFingers.
- For each of those calls, check that the incoming connection is allowed
to operate on that particular username
- Don't require a claimed device to list or remove fingerprints
- Clean up username and sender when releasing the device
- Modify the storage backend to not require an opened device to list
or delete fingerprints
- Add a simple test program to list registered fingerprints for the
usernames passed as argument
