memento: Fix memory leak

The memento should be deleted after it is restored.

Author: jclsn

src/Memento/Conceptual/main.cc

@@ -143,6 +143,7 @@ class Originator {
   void Restore(Memento *memento) {
     this->state_ = memento->state();
     std::cout << "Originator: My state has changed to: " << this->state_ << "\n";
+	delete memento;
   }
 };
 
@@ -229,4 +230,4 @@ int main() {
   std::srand(static_cast<unsigned int>(std::time(NULL)));
   ClientCode();
   return 0;
-}
+}