Exit game when server logs player out

If, for any reason, the server logs the player out and it doesn't appear on the received players list, it should exit the game.

No file or test is named. Start by locating the code that processes the received players list and handles server logout, then trace how the local player is identified. Done means the game exits when the server logs out that player and the player is absent from the received list.

Written by the indexing model from the issue text.