Player StationType changes across network when a player changes station externally by either leaving or entering. Full changelog included in commit message.

Full changelog:
- Network in engine has an extra function for returning the local ENet address. This is used in MainMenuEventreceiver to correctly store the sender his address.
- Player has extra functions for checking and setting the current StationType it occupies. This is stored as an unsigned int.
- Station has two new variables for holding the player currently using that station and a simple boolean for local checking if the player can be changed.

Problems:
- The player that functions as the server has a strange problem with his ENet address, because it never matches the address stored in the PlayerList. This causes the server player to never be found if he changes player, thus creating a problem with syncing and changing stations. This has to be fixed, but was not part of my task.
- It is not yet possible to leave a station so the code for changing the status upon a player leaving remains UNTESTED as of now.

Closes stories:
Under "Player can enter the station":
- Server responding by changing status of that player.
Under "Player can leave the station":
- Server responding by changing status of that player.
Merge branch 'Developer' of github.com:gametechnology/psi-2013 into Developer