Do not save fast edge removal property

This is not needed for further processing of the graph.

Trajectories/segments.py

@@ -101,6 +101,7 @@ print("Number of edges:", g.num_edges())
 print("Internal properties:")
 g.list_properties()
 print('Saving graph...')
+g.set_fast_edge_removal(False)
 g.save(sys.argv[2])
 t1 = time.perf_counter()
 timings_file.write(f'Done saving in {t1 - t0:.0f} s\n')