add recipe for default:gravel and clean up a bit (fixes #7)

crafting.lua

@@ -15,8 +15,6 @@ minetest.register_craft({
         output = "building_blocks:slab_marble",
         recipe = {
             { "darkage:marble", "darkage:marble","darkage:marble" },
-            { "", "", "" },
-            { "", "", "" }
         },
 })
 
@@ -25,7 +23,6 @@ minetest.register_craft({
         recipe = {
             { "stairs:slab_Marble", "" },
             { "homedecor:kitchen_cabinet", "" },
-            { "", "" }
         },
 })
 
@@ -34,7 +31,6 @@ minetest.register_craft({
         recipe = {
             { "stairs:slab_Marble", "" },
             { "homedecor:dishwasher", "" },
-            { "", "" }
         },
 })
 
@@ -60,17 +56,20 @@ minetest.register_craft({
         output = 'default:sand 8',
         recipe = {
                 {'default:gravel', 'default:stone', 'default:gravel'},
-                {'', '', ''},
-                {'', '', ''},
         }
 })
 
+minetest.register_craft({
+    output = 'default:gravel 8',
+    recipe = {
+        {'default:cobble', 'default:stone', 'default:cobble'},
+    }
+})
+
 minetest.register_craft({
         output = 'illuna:desert_gravel 8',
         recipe = {
                 {'default:desert_cobble', 'default:stone', 'default:desert_cobble'},
-                {'', '', ''},
-                {'', '', ''},
         }
 })
 
@@ -78,8 +77,6 @@ minetest.register_craft({
         output = 'illuna:desert_gravel 8',
         recipe = {
                 {'default:desert_cobble', 'default:desert_stone', 'default:desert_cobble'},
-                {'', '', ''},
-                {'', '', ''},
         }
 })
 
@@ -87,8 +84,6 @@ minetest.register_craft({
         output = 'default:desert_sand 8',
         recipe = {
                 {'illuna:desert_gravel', 'default:stone', 'illuna:desert_gravel'},
-                {'', '', ''},
-                {'', '', ''},
         }
 })
 
@@ -96,8 +91,6 @@ minetest.register_craft({
         output = 'default:desert_sand 8',
         recipe = {
                 {'illuna:desert_gravel', 'default:desert_stone', 'illuna:desert_gravel'},
-                {'', '', ''},
-                {'', '', ''},
         }
 })
 
@@ -107,7 +100,6 @@ minetest.register_craft({
     recipe = {
                 {'darkage:mud', 'default:gravel', ''},
                 {'default:gravel', 'darkage:mud', ''},
-                {'', '', ''},
             }
         })