Avoid looking at the game type to determine minishogi piece values.

Avoid looking at the game type to determine minishogi piece values.

We don't know how to determine the game type anyway, and a previous
patch disables its computation, but no need to compile dead code in this
case.

Another problem to look at is that "in_opening_stage" is surely
badly tuned for MiniShogi, but the program seems to score better with
current code that by telling there is opening stage.

Flag FIXME's where applicable so some willing soul would know where to
find things to improve for MiniShogi.