Further work on the 4 man end game tables

The work on the KPKP table base is quite challenging, because one has to consider the pawn promotions and also decide how to handle en passent positions. While working on the table it showed that there are some inconsistencies in the KQKP and other tables as well that popped up when handling the promotions. So I have to verify the base tables before I continue to work on the KPKP table. I hope to fix those issues pretty soon.