Constructors with default args

[gchenfc]

I think for some reason constructors with default args do not work. No time to figure out why atm.

e.g.

class JointObjectives : gtsam::NonlinearFactorGraph {
  JointObjectives(int j, int k = 0);
};

builds but does not allow the constructor JointObjectives(0) in python. Optional arg does not show up in gtdynamics.cpp file.

[gchenfc]

Nevermind - I think I just forgot to do a make clean or something. This works fine.