security: Added OnVerifiedInterest and OnVerifyInterestFailed.
tests (minor): In TestEncodeDecodeData.VerifyCallbacks, make the private member final.
Face (minor): makeCommandInterest needs to be public.
security: In PolicyManager, make skipVerifyAndTrust, requireVerify and checkVerificationPolicy support Interest also.
security: KeyChain: Added verifyInterest.
tests: In TestEncodeDecodeInterest, also sign and verify the interest.