typedef warnings when compiling MATLAB wrapper

[Frank Dellaert]

At some point, these started to appear:

/Users/dellaert/git/gtsam/build/wrap/gtsam_unstable/gtsam_unstable_wrapper.cpp:1827:50: warning: unused typedef 'Shared' [-Wunused-local-typedef]
  typedef boost::shared_ptr<gtsam::SimPolygon2D> Shared;

We should get rid of this. Might want to wait on @mattsklar python version of wrap.

[Frank Dellaert]

Fixed in PR #399