Fix a lot of errors

src/utility/objaddr.rs

@@ -48,20 +48,20 @@ impl ObjAddr {
 
     /// Searches for a semaphore of id **id** in self
     pub fn search_semaphore(&self, id: i32) -> Option<&mut Semaphore> {
-        self.semaphores.get(&id)
+        self.semaphores.get_mut(&id)
     }
 
     /// Searches for a lock of id **id** in self
     pub fn search_lock(&self, id:i32) -> Option<&mut Lock> {
-        self.locks.get(&id)
+        self.locks.get_mut(&id)
     }
 
     /// Removes the object of id **id** from self if it exists
-    pub fn remove_semaphore(&mut self, id: i32) {
+    pub fn remove_semaphore(&mut self, id: i32) -> Option<Semaphore> {
         self.semaphores.remove(&id)
     }
 
-    pub fn remove_semaphore(&mut self, id:i32) {
+    pub fn remove_lock(&mut self, id:i32) -> Option<Lock> {
         self.locks.remove(&id)
     }