safely popping out context after a client's disconnection from the
socket. any possible error get logged, although I think they're
irrelevant.
making `IONamespace` to force emiting messages to ALL members of the channel/room, including the sender.
saving initial positions in all players when starting a new ``Game``.
Making the game finish after the fifth goal.
Also added a new event listener for "board" in ``IONamespace`` for
debugging purpouses.
Fixing a ``Goal``'s timing issue, requires rebuilding the database.
``Game.score_board`` now works.