test in test_gamestate revealing problem in _remove_group
test in test_gamestate revealing problem in _remove_group

Rochester-NRT/AlphaGo,Rochester-NRT/AlphaGo,MaMiFreak/RocAlphaGo,Rochester-NRT/AlphaGo,hiropppe/RocAlphaGo,Rochester-NRT/RocAlphaGo,vftens/RocAlphaGo,wrongu/RocAlphaGo