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

stairs/.luacheckrc

@@ -0,0 +1,31 @@
+std = "lua51+luajit+minetest+stairs"
+unused_args = false
+max_line_length = 120
+
+stds.minetest = {
+	read_globals = {
+		"DIR_DELIM",
+		"minetest",
+		"core",
+		"dump",
+		"vector",
+		"nodeupdate",
+		"VoxelManip",
+		"VoxelArea",
+		"PseudoRandom",
+		"ItemStack",
+		"default",
+		"table",
+		"math",
+		"string",
+	}
+}
+
+stds.stairs = {
+	globals = {
+		"stairs",
+	},
+	read_globals = {
+		"stairsplus",
+	},
+}