Revert "Tweak bishop pair and knight weight"

This reverts commit 3cc47edf622b1d12a37b3637cae503d6862437c4.
Revert "Don't special case for abs(beta) >= VALUE_MATE_IN_MAX_PLY"

This reverts commit 55a3e0af8d0d1e169cc8b16541ffeb41e157b66e.
Merge branch 'master' of https://github.com/jarkkop/Stockfish