flagging multi-objective formulae as State formulae

src/storm/logic/MultiObjectiveFormula.cpp

@@ -19,6 +19,10 @@ namespace storm {
             return true;
         }
         
+        bool MultiObjectiveFormula::isStateFormula() const {
+            return true;
+        }
+        
         bool MultiObjectiveFormula::hasQualitativeResult() const {
             for(auto const& subformula : this->subformulas){
                 if(subformula->hasQuantitativeResult()){

src/storm/logic/MultiObjectiveFormula.h

@@ -12,6 +12,7 @@ namespace storm {
             virtual ~MultiObjectiveFormula();
             
             virtual bool isMultiObjectiveFormula() const override;
+            virtual bool isStateFormula() const override;
             
             virtual bool hasQualitativeResult() const override; // Result is true or false
             virtual bool hasQuantitativeResult() const override; // Result is numerical or a pareto curve