make stoch_simul more efficient: solve at `order=1` when `M_.hessian_eq_zero==1`
To avoid the error in matlab/stochastic_solvers.m line 64, when M_.hessian_eq_zero is true solve at order = 1 instead of 2 or 3.
Work to be done on a branch
To avoid the error in matlab/stochastic_solvers.m line 64, when M_.hessian_eq_zero is true solve at order = 1 instead of 2 or 3.
Work to be done on a branch