Added error message for unsupported Lap Swimming FIT files

Until proper handling is added better to give an error message,
otherwise an activity with no data is created causing confusion.

src/FitRideFile.cpp

@@ -960,6 +960,11 @@ struct FitFileReaderState
                 case 23: /*decodeDeviceInfo(def, time_offset, values);*/ break; /* device info */
                 case 18: decodeSession(def, time_offset, values); break; /* session */
 
+                case 101: /* lap swimming length */
+                    errors << "Unsupported Lap Swimming FIT File - Use .tcx or .pwx formats";
+                    stop = true;
+                    break;
+
                 case 2: /* DEVICE_SETTINGS */
                 case 3: /* USER_PROFILE */
                 case 7: /* ZONES_TARGET12 */