Fixing compilation on Linux
Fixing bug with name::Components::toVersion

There was a problem because of signed/unsigned char comparison mismatch
Preliminary experiments with OSX Keychain API
Template for keychain interface
Generalizing work with time and time intervals
Finally separating from C-API, code now incomplete and cannot be yet used
Import trie data structure from ndnSIM
Adding ndn::Face as a base class to dispatch interests and data packets
doc: Add UML diagram