[GRASS5] Color code cleanup

[Glynn Clements]

Cedric Shock wrote:

> Definitions of the rgb values for preallocated ("standard") colors are now in 
> colors.h. The major color related code (D_translate, G_str_to_color, and the 
> definitions of color tables in XDRIVER and PNG) have been updated to use 
> this. I haven't updated the named_colr.c code because I don't have an easy 
> way to test it. I haven't touched the postscript code, as it is quite 
> dissimilar.

If you've touched the colour-handling code in the display driver or
libraries, please test the changes on a colour-mapped display (e.g. 
"startx -- :1 -depth 8 -cc 3").

-- 
Glynn Clements <glynn at gclements.plus.com>