Gelato should fail with an informative error message if the user supplies a MATSim events file where link events appear out of chronological order

[mfitz]

As per this discussion, Gelato throws a LinkLogPassengerConsistencyException and terminates if the events file contains link events that do not appear in chronological order. Although this is the desired behaviour, the messaging to the user does not explain what they need to do (sort their events file into chronological order) to correct the error, so the user experience is a confusing one.

When the app terminates in this way, it should clearly explain the cause of the error and the action that the user should take. We should also document this requirement of the events file in the README.