game: changé le nom current_round par currentRound

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
game: renomé isPlayerInGame

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
game: remplacé List de players par Set

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
tests: ajouté les tests

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>