use inventory images for lava lamps

lavalamp/init.lua

@@ -26,7 +26,8 @@ for i in ipairs(lavalamps_list) do
 	                length=6.0,
 	            },
 	        },
-	    },    
+	    },
+		inventory_image = "lavalamp_lamp_"..colour.."_inv.png",
 	    paramtype = "light",
 	    paramtype2 = "facedir",
 	    sunlight_propagates = true,
@@ -78,7 +79,3 @@ for i in ipairs(lavalamps_list) do
 	
 end
 
-
-
-
-