Add Rubber Goo as replacement for the grinder (#578)

Fixes the circular dependency in issue #474 by adding a new item that can be used to craft Rubber.

technic/crafts.lua

@@ -174,7 +174,6 @@ minetest.register_craft({
 	},
 })
 
-
 minetest.register_craft({
 	output = "default:dirt 2",
 	type = "shapeless",
@@ -186,3 +185,25 @@ minetest.register_craft({
 		"group:sand",
 	},
 })
+
+minetest.register_craft({
+	output = "technic:rubber_goo",
+	type = "shapeless",
+	recipe = {
+		"technic:raw_latex",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+		"default:coal_lump",
+	},
+})
+
+minetest.register_craft({
+	output = "technic:rubber",
+	type = "cooking",
+	recipe = "technic:rubber_goo",
+})

technic/items.lua

@@ -134,6 +134,11 @@ minetest.register_node("technic:machine_casing", {
 	sounds = default.node_sound_stone_defaults(),
 })
 
+minetest.register_craftitem("technic:rubber_goo", {
+	description = S("Rubber Goo"),
+	inventory_image = "technic_rubber_goo.png",
+})
+
 for p = 0, 35 do
 	local nici = (p ~= 0 and p ~= 7 and p ~= 35) and 1 or nil
 	local psuffix = p == 7 and "" or p