Add move constructor and move assignment operator

[Eshan]

Addition of move constructor

    T(T&& obj): data(std::move(obj.data)) { obj.data = nullptr }     //  enables the resources owned by an rvalue object to be moved into an lvalue without copying

move assignment operator

    T& operator=(T&& obj) { data = std::move(obj.data); return *this; }     //  enables the resources owned by an rvalue object to be moved into an lvalue without copying

This is important because a person is bound to come across these eventually. Although it might be a bit advanced for someone who is just starting out.