dtss: observable names in Simulator

src/artis-star/kernel/dtss/Simulator.hpp

@@ -137,6 +137,11 @@ namespace artis {
             common::Value observe(const typename Time::type& t,
                     unsigned int index) const { return _dynamics.observe(t, index); }
 
+            virtual std::string observable_name(unsigned int observable_index) const
+            {
+                return _dynamics.observable_name(observable_index);
+            }
+
             void output(const typename Time::type& t)
             {