reduce PV nodes like non PV nodes (3543704)
Revert "reduce PV nodes like non PV nodes (3543704)"

15000 games in 10+0.1, early stopped manually
Score of ./Stockfish/pv vs ./Stockfish/stockfish: 2953 - 3151 - 6709  [0.492] 12813

This reverts commit 4cb088594b4758f697485d90cb837c6fc1084529.
qsearch SEE and evasion pruning also at PV nodes (4270628)
singular extension: same min depth for PV nodes as non PV nodes (4101649)
Merge branch 'master' into pv
Merge branch 'master' into pv