optimized low temp colors

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@39188 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/gis/colors/celsius

@@ -1,6 +1,6 @@
--80 0 0 50
--30 0 10 128
--20 22 22 130
+-80 0 0 40
+-40 violet
+-20 white
 -10 0 0 150
 0 0 0 255
 10 green