Stockfish KPK bitbase
Copy-paste (and adapted) the code from Stockfish to generate the KPK bitbase. This patch is non functional, and the KPK bitbase is just initialized but not actually used in the eval for the moment. Next step is to do some "random checks", to make sure it's OK. Then implement a material key in the board. Then probe bitbase to evaluate KPK endgame. More endgame knowledge will follow.
No functional change.
signature = 6727896