Minor makefile cleanups, added support for json linting.

Makefile
--------
   o Update copyright notice.
   o Added -o pipefail for enhanced error detection.
   o Begin normalizing makefile target behavior for automation.
   o Added suppport for linting json source.
   o lint: iterate over files so errors are displayed alongside source.
   o Replace inlined commands with macros allowing overrides.
   o Added targets help and todo as reference material.

Change-Id: Ie0780008ed575c17b655bfa9e6940f72288873c6
1 file changed