Fixing the regression in behavior in evaluate_planner_objective (Ref: #1680)

• evaluate_planner_objective now returns conditional welfare depending on the initial value of the Lagrange multipliers when it is suitable to do so
• histval blocks are no longer ignored
• Incidentally fixes a problem with the setting of auxiliary variables, which were not correctly set if there were auxiliaries after the Lagrange multipliers
• The perfect foresight syntax for shocks can now be used to specify the shock contained in the information set.