pseudo isolated pawn (6166157)
also improve "hole" condition as a result.
generalize chainable condition in passed pawn potential support (6393948)
simplify and generalize chainable passer (6162408)

isolated vs. master(e58da2d078ce21905cda5b18df3dda61bbfe5781)
tc=inf nodes=40000 book=book.bin (no bookdepth limit, on purpose)

Score of ./chess/isolated vs ./chess/master: 3291 - 3096 - 3613  [0.510] 10000