KeyLocator: Deprecate the use of a digest attached to the KeyName.  Added ndn_KeyLocatorType_KEY_LOCATOR_DIGEST
Interest: Added keyLocator.  Deprecate publisherPublicKeyDigest - if needed then the keyLocator type is KEY_LOCATOR_DIGEST and the key data has the digest.
Sha256WithRsaSignature: Deprecated getPublicKeyLocator.  If the signature has a public key locator, its keyLocator has type KEY_LOCATOR_DIGEST and the key data has the digest.
tests: In test-encode-decode-data: In dumpData, check for KeyLocatorDigest.
encoding: In TLV Signature, use KeyLocator KEY_LOCATOR_DIGEST if present.
tests: In test-encode-decode-interest: In dumpInterest, show the KeyLocator.
code style: fix indentation.
encoding: In TLV Interest, support KeyLocator.