Fixed 2 minor route issues

One fix ensures that if a railroad has no valid routes, it will gracefully display no routes rather than raise an exception. This is only possible for Illinois Central and Grand Trunk, as the other 5 all have legal routes from their home city.

The other fix was to re-enable the route C5 -> D6 (Chicago Connections to Chicago). Incorrect filtering logic caused it to be marked as invalid. In reality, as long as the railroad has a station on Chicago, it's always legal (assuming the phase 2 tile or higher has been placed).