Graph legend.

legend(string1,string2,string3, ...) puts a legend on the current plot using the specified strings as labels. legend works on line graphs and histograms, etc.

legend(x,y,string1,string2,string3, ...) puts a legend on the current plot at position (x,y), otherwise it defaults to the top left-hand corner.

legend(x,y) repositions an already defined legend.

legend(pos,string1,string2,string3, ...) puts a legend on the current plot with one of several predefined positions: 

        1 = Upper right-hand corner 
        2 = Upper left-hand corner  (default)
        3 = Lower left-hand corner
        4 = Lower right-hand corner

legend(pos) repositions an already defined legend.

Example: 

	w=gfx.Window()
	p1=w:plot({1,10},{1,10},'bo-') 
	p2=w:plot({5,5},{5,3},'rx-')  
	w:legend('blue line','red line');
	w:legend(4)