TrafficControl: Opposite Direction TDD Case (2)

After fixing the first issue with trains that can't find adjacent stations, a new issue has been seen.

The train arrives to Gärsnäs and is supposed to enter the track Sim-GarW at end position (12000). It should move to position 0 and enter Simrishamn. However, it enters the track at start position (Simrishamn) and moves towards Gärsnäs. 

The train state model needs to handle the reversed scenario. A bool reversedTraffic with a get/set method is added to the track object. 

I made changes in the methods train::readyToRunning, train::runningState and train::runningToOpening. 

The train needs to consider its direction (normal or reversed) when entering a track.

train::runningState introduces a virtual position, that is

• virtualPosition = position, if train isn't travelling in reversed direction,
• virtualPosition = track length - position, if train is travelling in reversed direction

With these changes, the train is able to travel in reversed direction.

A crash was found for train::setTrackPosition(0). When it is updating the position, the method track::getCoordinatesFromPosition asserted if the position was 0, since it was trying to access coordinates at index -1.