Improve backwards compatibility in Java std::vector wrappers

For users who have typemaps for the parameters in the add and set methods
(now called doAdd and doSet).
Also for users who have typemaps for the get method - revert the return
type for get (now called doGet) back to the same return type as
std::vector::at. Correct definitions of const_reference to match the
those in the (C++11) standard.
1 file changed