void color_area(int start, int end, char *colorname)
Colors text region from position start to position end with
color colorname (see the standard X11 file rgb.txt). This function
can be used with the Smac regexp interface to color strings of your
own modes (see color.sc §5.11 page ).
Removes all colors in the current buffer.
Returns 1 if your display is monochrome, else 0.