Removed unused typedef warning.

example/doc_how_to_use.cpp

@@ -36,7 +36,6 @@ typedef list<MyClass, MemberOption> MemberList;
 int main()
 {
    typedef std::vector<MyClass>::iterator VectIt;
-   typedef std::vector<MyClass>::reverse_iterator VectRit;
 
    //Create several MyClass objects, each one with a different value
    std::vector<MyClass> values;