Travel time validation

[sebhoerl]

For the last TRB paper on discrete mode choice, we were verifying that the predicted travel times in the choice model are in line with the ones actually observed in the simulation after several iterations. We should add this validation as a default output.

Plus, this will go well with the investigations by Milos and Aurore on settings network capacities properly, and it will be interesting to test the standard travel time estimation procedure that takes into account travel times of the last iteration vs. smoothing travel times over several iterations.