add module system and move sensor into core with it

src/util/id.rs

@@ -1,9 +1,9 @@
-/// intentionally does not implement copy or clone
+/// intentionally does not implement copy or ~~clone~~ HEEELP
 /// which should make it harder to misuse;
 /// the idea is to generally try to guarantee all IDs
 /// point to something valid, although duplicate
 /// gets around this if needed
-#[derive(Eq, Hash, PartialEq, Debug)]
+#[derive(Eq, Hash, PartialEq, Debug, Clone)]
 pub struct Id(u64);
 
 #[derive(Default)]