adds GameOver event, sorts out timing options and _result (no more _resultDetails) in Game
removes unused timing options in Game and renames increment to timeIncrement
removes Game states - only need isInProgress() now, which checks whether _endTime is null
adds isInProgress and removes getResultType in Game
removes if(state == IN_PROGRESS) check from Game.move
changes Game._gameOver to only take a Result, not set _state, and to fire GameOver