Add support for MAV_CMD_DO_FLIGHT_TERMINATION

* https://mavlink.io/en/messages/common.html#MAV_CMD_DO_FLIGHTTERMINATION

Signed-off-by: Ryan Friedman <Ryan.Friedman@avinc.com>

Author: Ryan Friedman

GCSViews/FlightData.cs

@@ -197,6 +197,7 @@ public enum actions
             Do_Parachute,
             Engine_Start,
             Engine_Stop,
+            Terminate_Flight,
         }
 
         private Dictionary<int, string> NIC_table = new Dictionary<int, string>()
@@ -1748,6 +1749,13 @@ private void BUTactiondo_Click(object sender, EventArgs e)
                         param3 = 1; // baro / airspeed
                     }
 
+                    if (CMB_action.Text == actions.Terminate_Flight.ToString())
+                    {
+                        MainV2.comPort.doCommand(MainV2.comPort.MAV.sysid, MainV2.comPort.MAV.compid, MAVLink.MAV_CMD.DO_FLIGHTTERMINATION, 1.0f, 0, 0, 0, 0, 0, 0);
+                        ((Control)sender).Enabled = true;
+                        return;
+                    }
+
                     if (CMB_action.Text == actions.Preflight_Reboot_Shutdown.ToString())
                     {
                         MainV2.comPort.doReboot();