Made it an error for track vertices to be on other tracks. This was a bug to have been allowed in the first place. Unfortunately, there were some submitted solutions that became invalid due to this change.

Fixed bug where routes from a signal were added multiple times and required removing all the dumplicates via UI to remove a path.

Fixed bug where terminal signals weren't being correctly removed from route highlighting mode.

Fixed buggy rendering where culling lagged behind for fast camera movement when following a train.