Extending constructors for lin_prog::MehrotraCtrl, lin_prog::IPFCtrl, and LinProgCtrl to use different behavior based upon whether the problem is specified as dense or sparse (the normal KKT system is solved in the former case, and the regularized augmented KKT system in the latter). Furthemore, the python IPM examples were modified to include a dense column in the linear constraint matrix in order to make use of the augmented system solver.