add another computer player without pondering
add another computer player without pondering

reason for the change: it's better to give users another challenge
that is not so heavy on the battery.

there are now 4 pre-defined computer players in total, 2 without
pondering and 2 with pondering.

herzbube/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego