doc: Updated README file and added new AUTHORS file

Change-Id: Id855c512225b88910f18b3dede8102502af8b6dd
src: Another round of source updates: moving all headers close to implementation files

Change-Id: I3d47076504950e67746174623c75383948e9d93d
build+src: Updating common.hpp to import (std|boost)::(shared_ptr|function|...) into ndn namespace

Also fixing a small bug in wscript.

Change-Id: I8f20caa177cc015b7433d1ecd3db385f533437c6
util: Importing scheduler, originally implemented in NFD

The scheduler uses monotonic clock whenever available.

This commit also includes an example to show how to work with the
scheduler.

Change-Id: I006bcc6afddd33caa8d1ec9575c0596234315411