When calling Clear on UniquePtrList, also clear the vector.

src/Memory/__OptionalUniquePtrList.hpp

@@ -38,6 +38,7 @@ namespace ArbUt {
             for (auto& i : _vector) {
                 delete i;
             }
+            _vector.clear();
         }
 
         /// @brief Borrow a pointer at a certain index.

src/Memory/__UniquePtrList.hpp

@@ -43,6 +43,7 @@ namespace ArbUt {
             for (auto& i : _vector) {
                 delete i;
             }
+            _vector.clear();
         }
 
         /// @brief Borrow a pointer at a certain index.