[shogi-server] Improve timed-up detection.

[shogi-server] Improve timed-up detection.

Previously, the server checked if a game got timed up when a player
in turn sent no message for a certain amount of time mainly defined
by Default_Timeout. If the player sent keep alive frequently, the
timed-up detection could be quite delayed.
This issue has been addressed. The server now checks timed up with
keep alive received as well. Players are notified with TIME_UP not
long before games gets timed up.