prevent crash in setting sky color

if get color from name return nil

init.lua

@@ -668,11 +668,13 @@ function unifieddyes.on_airbrush(itemstack, player, pointed_thing)
 			minetest.chat_send_player(player_name, "*** No node selected")
 		else
 			local hexcolor = unifieddyes.get_color_from_dye_name(painting_with)
+			if hexcolor then
 				local r = tonumber(string.sub(hexcolor,1,2),16)
 				local g = tonumber(string.sub(hexcolor,3,4),16)
 				local b = tonumber(string.sub(hexcolor,5,6),16)
 				player:set_sky({r=r,g=g,b=b,a=255},"plain")
 			end
+		end
 		return
 	end
 
@@ -1431,7 +1433,7 @@ for _,i in ipairs(unifieddyes.base_color_crafts) do
 
 			minetest.register_craft( {
 				type = "shapeless",
-				output = "dye:"..j[1]..color..j[2].." "..yield,
+				output = "dye:"..j[1]..color..j[2].." "..j[6],
 				recipe = {
 					"dye:"..color,
 					firstdye,