the implementation of seki support is incomplete.
needs unit test cases.
Remove non-const function Time() and decouple time measurement from tracking the time left at a node. This class should not have to deal with time measurement, instead add a time parameter to AddMove() that informs the game about the time that needs to be subtracted from the time left.
Also ensure in GoGame that the time settings and time left records always reflect the state at the current node. This should be implemented in GoBoardUpdater::Update(), which is used by GoGame.