r305: - added IDL and test code for samr_RidToSid()

r305: - added IDL and test code for samr_RidToSid()

- completed the IDL and test code for the various set user password
  mechanisms in samr. Three password mechanisms are now working, the
  UserInfo24 method, the OemChangePasswordUser2() method (which only
  sets the LM password) and the ChangePasswordUser2() method which sets
  both the LM and NT passwords.

- updated some crypto routines to support the password change tests
(This used to be commit 051efa2abf9d1fbbf783df411c02f2714027f813)