Get rid of TableStartedPlaying event

This event was introduced to prevent illegal dealer changes. But it turned out that mistakes happen, and in some cases it is justified to make another person the dealer. Having to suspend and resume the game to do so, seems overkill.

It may be a good idea though to introduce an aggregate 'GameSequence', to hold a sequence of games, played by the same people. Changing the players group on a table, could create a new GameSequence. A game sequence being created/started, would then indicate that the players at the table have started playing.