create proper stairs mod replacement; create option to allow registering stairs w/out a proper recipeitem

stairs/init.lua

@@ -0,0 +1,33 @@
+local modname = minetest.get_current_modname()
+local modpath = minetest.get_modpath(modname)
+local S = minetest.get_translator(modname)
+
+stairs = {
+	version = {3, 0, 0},
+	fork = "minetest_mods",
+
+	modname = modname,
+	modpath = modpath,
+
+	S = S,
+
+	has = {
+		default = minetest.get_modpath("default"),
+		i3 = minetest.get_modpath("i3"),
+		stairs = minetest.get_modpath("stairs"),
+		unified_inventory = minetest.get_modpath("unified_inventory"),
+	},
+
+	log = function(level, messagefmt, ...)
+		return minetest.log(level, ("[%s] %s"):format(modname, messagefmt:format(...)))
+	end,
+
+	dofile = function(...)
+		return dofile(table.concat({modpath, ...}, DIR_DELIM) .. ".lua")
+	end,
+}
+
+stairs.dofile("util")
+stairs.dofile("legacy")
+stairs.dofile("api")
+stairs.dofile("compat")