Lua: added 'matchcolor2' that uses DawnBringer's perceptual formula. Updated scripts numbering to 2.4

git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1797 416bcca6-2ee7-4201-b75f-2eb2f807beb1

share/grafx2/scripts/samples_2.4/brush/GrayscaleAvg.lua

@@ -0,0 +1,24 @@
+--BRUSH Remap: Grayscale (average)
+--by Richard Fhager 
+--http://hem.fyristorg.com/dawnbringer/
+
+-- Copyright 2010 Richard Fhager
+--
+-- This program is free software; you can redistribute it and/or
+-- modify it under the terms of the GNU General Public License
+-- as published by the Free Software Foundation; version 2
+-- of the License. See <http://www.gnu.org/licenses/>
+
+w, h = getbrushsize()
+
+for x = 0, w - 1, 1 do
+ for y = 0, h - 1, 1 do
+   
+   r, g, b = getcolor(getbrushpixel(x,y))
+
+   a = (r+g+b)/3
+
+   putbrushpixel(x, y, matchcolor(a,a,a));
+
+ end
+end