Dispatcher improvements.

[metromar]

Hi !

First of all : thanks for this game. It's the game I was dreaming of since my childhood. 

Buuuut some improvements can be made in this game, especially for dispatcher mode : 

- We need a coordinator for dispatcher. For exemple if a train is delayed, the chief dispatcher can say to all dispatcher that x train is delayed. Also to say x train can be overtaken at x station etc... like a administrator in a server.

- We need to have access to all signal boxes when choosing in multiplayer and espacially Lazy zone because the AI cannot handle it. We also need to be able to be 2 or 3 in one signal box. 

- A tutorial for the older signal boxes. 

- Better communication with AI signal boxes (we cannot repeat to them, sometimes they don't awnser to player signal box...)

- Ability to change signal box without quitting the server.