[computer-go] Mogo: tree preservation

[Darren Cook]

> It preserves the tree if and only if you add:
> --pondering 1
> 
> If you don't want to use pondering, but you still want to keep the tree
> between moves, add
> --keepTreeIfPossible 1
> 
> (not documented, and from my memory, it may be not the right option :p)

Good guess, that worked. It sometimes is worth 10,000 nodes, sometimes
is worth around 180,000 nodes (i.e. depending on if I play the move it
expected or not).

Thanks,
Darren