delete a player from player list if the player processes crashed

[clonejo]

this blocks successful login after a connection crash

[clonejo]

Connection crashes are handled correctly now. Since we have no supervisor for the player processes we can't remove their player record when those crash. (If we want to avoid a supervisor we can also use try/catch.)

Reopen if you think this is worth an issue.

[clonejo]

Future solution: Have a supervisor for those player processes.