Draft: Allow configuration of simulation start time in model.props file

include/model/model.h

@@ -72,6 +72,7 @@ public:
 protected:
 
     /*Variables that describe properties of the model*/
+    double start_at;                        //!< first time step in profile that is simualted
     unsigned long stop_at;                  //!< number of RepastHPC ticks to simulate
     double step_size;                       //!< size of a simulation time step in seconds
     bool use_commdata;                      //!< true if files for latency and PER values are used,