Update 5.1 released

We have fixed some small, but pretty important things:

• Fixed problem with passengers unable to enter one of the buses;
  
• Fixed passengers' position inside of modern Russian bus;
  
• Added Manual gearbox checkbox for Tutorial mode;
  
• Added possibility to create your own livery for big European bus;
  
• Fixed bus in 2nd Cologne Scenario, which made it impossible to finish this Scenario successfully.