Route highlighting and dead ends

* Fixed highly related, but technically separate bugs where trains didn't handle reversing at track terminations correctly when there were no valid exits. In the simulation, the train was allowed to reverse, and would go somewhere, but with the bug fix it prints a run-time error. Similarly, the route highlighting was incorrectly allowing invalid paths through one-way signals to be highlighted. However, the incorrect train path and high-lit routes were different, so it was extra buggy. This change required a game version bump because it is changing the simulation results, although I really hope people weren't depending on incorrect behavior of track terminations.

* Draw circles where depots can be placed.

* When both the track and signal on it were selected, pressing Delete wouldn't delete the track. Thus pressing Control+A then delete would not delete everything.

* Fixed simulation determinism issues by adding and adjusting sort conditions.