
    * Change from line-based to paragraph-based content checking,
      in order to catch draft references broken across lines, and
      other text broken across lines.  (Collect paragraph before
      call to checkline() .)

    * Obsoletes:

      - Warn when a document says it updates/obsoletes one at a higher  
	standards level
      - remove RFCs listed there from the Obsolete reference warnings

    * Add warning for missing contact address

    * Add a test for the existence of newer idnits versions, and
      possibly download.

    * Add more experimental warnings:

      - URL reachability (needs paragraphs)
      - ABNF verification
    
