Use move_pawns() in Pawns::probe

And rename some stuff.

No functional change.
Don't calculate pawnsOnSquares twice

And reformat some code while there.

No functional change.
Rename piece_count and piece_list

No functional change.
phash: pruned records go into a _pruned.hsh file
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into kyoto
epdimport: fix for changes to piece_list and piece_count on the Stockfish trunk. Why Marco why?