Plane: implement MAV_CMD_REQUEST_AUTOPILOT_CAPABILITIES

ArduPlane/GCS_Mavlink.pde

@@ -1219,6 +1219,14 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
             }
             break;
 
+        case MAV_CMD_REQUEST_AUTOPILOT_CAPABILITIES: {
+            if (packet.param1 == 1) {
+                gcs[chan-MAVLINK_COMM_0].send_autopilot_version();
+                result = MAV_RESULT_ACCEPTED;
+            }
+            break;
+        }
+
         default:
             break;
         }