[CM] gnuplot support

[Rick Taube]

CVS head now has new Gnuplot support for plotting data sets and  
output from musical processes. See new dictionary entry for overview  
and examples:

	http://commonmusic.sf.net/doc/dict/gnuplot-fn.html

Ive tested in both SCheme (guile gauche) and Common Lisp. With a few  
trivial edits the main file (gnuplot.scm) should work in any Scheme  
with keywords, ie it doens't really depend on Common Music.

The new gnuplto support works with Gnuplot release 4.2.rc2

To use Gnuplot on OSX you need to install AquaTerm for OSX in / 
Applications and then install gnuplot itself.

--rick