is contradictory with diffuse_filter or unit_root_variables
declaration. Models with non-stationary variables, but only stationary
observed variables need diffuse_filter option and make a useless call
to kalman_filter_d (this seems better than trying to distinguish these
rare cases)
parameters and also for the estimation of the initial states).
Added specialized routines for steady state kalman filter.
Completed header of DsgeLikelihood (missing refs to the routines called by DsgeLikelihood).