Update Native Maps to use more recent C++ standards

It may also help us to move away from raw pointers for internal objects where we can use RAII to better manage resources. Only top level objects need a java managed lifetime. everything else should use smart pointers. this alleviates any potential concern for memory leaks and also allow us to better manage object lifetimes.

Further, I think we can better exploit move semantics and improve performance. As a final task in this, we should look at copy semantics where they are employed. It seems that memory is copied quite a bit. In some cases it is not avoidable, but it would behoove us to evaluate their usages.