implemented lock_release in thread_manager.rs, for this, I derived the clone function for lock in synch.rs and list in list.rs

src/utility/list.rs

@@ -10,6 +10,7 @@ use std::ptr;
 /// but everything has been tested with miri to assure there's no Undefined Behaviour (use-after-free, double free, etc.)
 /// or memory leak
 #[derive(PartialEq)]
+#[derive(Clone)]
 pub struct List<T: PartialEq> {
     head: Link<T>,
     tail: *mut Node<T>,