TTClust 4.7.0

2 new functionalities:

• multiple trajectories reading (trajectories will be concatenated).
  To read multiple trajectories, just add them after the "-f" argument (like "-f traj1.xtc traj2.xtc" or "-f traj*.xtc)
• striding (read every *th frames) with the "-s" argument ("-s 10" to read every 10th frames)