Feature/constraint analysis workshop updates

Disabling the gust and landing field length constraints caused the boundary vector to be empty, which resulted in errors. Fixed this issue

constraint_analysis/include/constraint_analysis/ca_functions.h

@@ -184,6 +184,7 @@ namespace Mattingly {
          */
         auto min_speed(double CL_max, double altitude, double Mach,  double weight_fraction) -> const double;
 
+        auto constraint_analysis::approach_speed(double V_app, double CL_max, double weight_fraction, double s_A, double C_D, double h_obs, double k_TD, double altitude) -> const double;
     private:
 
         // Membervariables