Also, this commit imports used classes from ::ndn namespace (from NDN-CPP library) directly to ::nfd namespace. refs: #1163 Change-Id: I9cc9d72e00af495b4ed0c84e6d418a7c9ba986cb
refs #1127 Change-Id: Ie0bc1fc2ddcc61dd1f1cf10fb1935edde4aff6c5