[ Henry Stern ]
* Add JSON input and output support, including new libnmsg functions
  nmsg_input_open_json(), nmsg_output_open_json(), nmsg_message_from_json(),
  and nmsg_message_to_json(); new -j and -J command line options for
  nmsgtool; and new per-field 'format' and 'parse' methods in the msgmod
  plugin API.

[ Chris Mikkelson ]
* nmsg_chalias_free(): Check for null aliases list.