Add #[inline(never)] to native calls.
Refactor test.rs.
Passes and returns wx class objects as managed pointers(boxes).

 * To emulate class inheritance, we are using generic methods(member functions).
 * Passing parameters to generic functions doesn't copy and moves the value always.
 * So if you want pass a wx object to a (member) function and yet another function, you have to clone the value everywhere.
 * To work around this, let wx*::new*() returns @-ptr.