Messages from game server to ggzd

Table of Contents
LOG -- Log message from the game
GAME_STATE -- Request of game state change
NUM_SEATS -- Request of seat count change
BOOT -- Request of player/spectator boot
BOT -- Request to fill seat with bot player
OPEN -- Request to open seat
GAME_REPORT -- Notification of game results
SAVEGAME_REPORT -- Notification of temporary savegame location