histval to set initial condition for Kalman filter
conditional_forecast-commands (also improves documentation)
histval-block specification should be independent of whether
loglinear is used or not (as is the case with e.g.
steady_state_model). This requires Dynare taking the log automatically when required. This clashes with
conditional_forecast_path-block, where the specified controlled values are never transformed.
ramsey-command, which seems to in principle allow for
histval. Should we try to make it compatible or provide an error?