Improve the enumeration of biometric devices

[resilar]

The current code locates fingerprint sensor devices by enumerating the registry tree HKLM\System\CurrentControlSet\Enum. A better approach would be to use SetupDi* family of functions to enumerate the biometric device class, i.e., ClassGuid = {53D29EF7-377C-4D14-864B-EB3A85769359}.