Make posters dyeable (#20)

* set signs param2 to colorfacedir

- make signs use a color palette and hardware coloring
- add poster coloring crafting recipes and optional depend on dye

* use xcompat

* optipng textures

* make recipe shapeless

* fix spaces/tab mix

* remove xcompat check

signs/crafts.lua

@@ -48,6 +48,24 @@ minetest.register_craft({
 	}
 })
 
+local dyes = {
+	mat.dye_white,
+	mat.dye_grey,
+	mat.dye_orange,
+	mat.dye_brown,
+	mat.dye_dark_grey,
+	mat.dye_yellow,
+	mat.dye_green,
+	mat.dye_red,
+}
+for i, dye in ipairs(dyes) do
+	minetest.register_craft({
+		type = "shapeless",
+		output = minetest.itemstring_with_palette("signs:paper_poster", (i-1) * 32),
+		recipe = {"signs:paper_poster", dye},
+	})
+end
+
 minetest.register_craft({
 	output = 'signs:label_small',
 	recipe = {