security: Add attribution to ndn-cxx security by Yingdi Yu.
Face: Fix bug in reconnectAndExpressInterest: remove the non-standard whitespace character.
security: Added MemoryIdentityStorage.
security: Added MemoryPrivateKeyStorage, SelfVerifyPolicyManager, IdentityManager and KeyChain.
tests: Added node/test-encode-decode-data.
tests: In browser/test-encode-decode-data, use a KeyChain instead of the deprecated data.sign().
Merge branch 'master' into feross including security API code including KeyChain. This moves
the work of sign and verify to MemoryPrivateKeyStorage and SelfVerifyPolicyManager.