running programs. Prompted by a mail from thuban at yeuxdelibad.net
and an old diff from Ralf Horstmann that I probably missed
because it was sent to ports@ rather than the maintainer.
Convert MESSAGE to README while there.
cairo is needed it's a little more complicated than before. @comment syweb's
install_rrdtool script which is no longer needed.
pointed out by Giancarlo Razzolini.
