Fix undeclared global variable warnings

Closes #26 (trivial)

class_layout.lua

@@ -458,7 +458,7 @@ function DigtronLayout.deserialize(layout_string)
 	if not layout_string or layout_string == "" then
 		return nil
 	end
-	deserialized_layout = minetest.deserialize(layout_string)
+	local deserialized_layout = minetest.deserialize(layout_string)
 
 	self.all = deserialized_layout.all
 	self.controller = deserialized_layout.controller

nodes/node_crate.lua

@@ -182,6 +182,7 @@ local loaded_on_recieve = function(pos, fields, sender, protected)
 		meta:set_string("title", minetest.formspec_escape(fields.title))
 	end
 	local title = meta:get_string("title")
+	local infotext
 	
 	if protected then
 		infotext = title .. "\n" .. S("Owned by @1", sender:get_player_name())