No functional change

Compensate by giving the Hanging bonus to weak doubly-attacked
non pawn enemies pieces.

STC: http://tests.stockfishchess.org/tests/view/5bfd53c40ebc5902bced9237
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 62107 W: 13664 L: 13622 D: 34821

LTC: http://tests.stockfishchess.org/tests/view/5bfd74700ebc5902bced9618
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 86406 W: 14381 L: 14365 D: 57660

A possible follow up would be to tune the hanging bonus and/or try to
simplify the hanging bonus condition.

Bench: 3810849

Currently we apply a penalty in continuation history for refuted TT moves.
We can use the same idea to also penalize refuted killer moves in continuation
history.

STC:
http://tests.stockfishchess.org/tests/view/5c00ccbd0ebc5902bcedd768
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 54366 W: 12086 L: 11687 D: 30593

LTC:
http://tests.stockfishchess.org/tests/view/5c0107880ebc5902bceddc9c
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 25457 W: 4302 L: 4078 D: 17077

Bench: 3419069

Exclude doubly protected by pawns squares when calculating attackers on
king ring. Idea of this patch is not to count attackers if they attack
only squares that are protected by two pawns.

STC
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 70040 W: 15476 L: 15002 D: 39562
http://tests.stockfishchess.org/tests/view/5c0354860ebc5902bcee1106

LTC
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 16530 W: 2795 L: 2607 D: 11128
http://tests.stockfishchess.org/tests/view/5c0385080ebc5902bcee14b5

This is third king safety patch in recent times so we probably need
retuning of king safety parameters.

Bench: 3057978

MOVE_NONE is represented as SQ_A1 to SQ_A1 which is never pseudo_legal.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 38807 W: 8363 L: 8275 D: 22169
http://tests.stockfishchess.org/tests/view/5c05f11d0ebc5902bcee4c86

No functional change

Remove the F[] array which I find unhelpful and rename `improvingFactor` to
`fallingEval` since larger values indicate a falling eval and more time use.

I realise a test was not strictly necessary, but I ran STC [-3,1] just to
check there are no foolish errors before creating the pull request:

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 35804 W: 7753 L: 7659 D: 20392
http://tests.stockfishchess.org/tests/view/5bef3a0c0ebc595e0ae39c19

It was then suggested to clean the constants around `fallingEval`
to make it more clear this is a factor around ~1 that adjusts time
up or downwards depending on some conditions. We then ran a double
test with this simplification suggestion:

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 68435 W: 14936 L: 14906 D: 38593
http://tests.stockfishchess.org/tests/view/5c02c56b0ebc5902bcee0184

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37258 W: 6324 L: 6230 D: 24704
http://tests.stockfishchess.org/tests/view/5c030a520ebc5902bcee0a32

No functional change

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 20816 W: 4525 L: 4402 D: 11889
http://tests.stockfishchess.org/tests/view/5c017cb90ebc5902bcede5b4

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 39287 W: 6401 L: 6309 D: 26577
http://tests.stockfishchess.org/tests/view/5c01825e0ebc5902bcede686

Bench: 3773021

This reverts commit 33d9548 ,
which crashed in DEBUG mode because of the following assert in position.h

````
Assertion failed: (is_ok(m)), function capture, file ./position.h, line 369.
````

No functional change

STC: (yellow)
LLR: -2.94 (-2.94,2.94) [0.00,5.00]
Total: 48919 W: 10625 L: 10517 D: 27777
http://tests.stockfishchess.org/tests/view/5c07e6a20ebc5902bcee7395

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 50360 W: 8424 L: 8102 D: 33834
http://tests.stockfishchess.org/tests/view/5c0812450ebc5902bcee76f4

Bench: 3775064

I've gone through the RENAME/REFORMATTING thread and changed everything I could find, plus a few more. With this, let's close the previous issue and open another.

No functional change.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 13323 W: 3015 L: 2818 D: 7490
http://tests.stockfishchess.org/tests/view/5c00a2520ebc5902bcedd41b

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 52294 W: 9093 L: 8756 D:34445
http://tests.stockfishchess.org/tests/view/5c00b2c40ebc5902bcedd596

Some obvious followups to this are to further tune this PSQT, or
try 8x8 for other pieces. As of now I don't plan on trying this
for other pieces as I think the majority of the ELO it brings is
for pawns and kings.

Looking at the new values, the differences between kingside and
queenside are quite significant. I am very hopeful that this a
llows SF to understand and plan pawn structures even better than
it already does. Cheers!

Closes #1839

Bench: 3569243

Joint work by SFisGOD, xoroshiro and Chess13234.

This combo consists of the following tweaks:
Assorted bonuses and penalties by SFisGOD
Bishop and Rook PSQT by SFisGOD
Tempo Value by xoroshiro
Futility pruning by Chess13234

STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 9005 W: 2082 L: 1882 D: 5041
http://tests.stockfishchess.org/tests/view/5c11628c0ebc5902ba119e90

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 44207 W: 7451 L: 7157 D: 29599
http://tests.stockfishchess.org/tests/view/5c1172a40ebc5902ba119fa3

Bench: 3332460