Even more spelling fixes

No functional change.
Clarify definition of capture_or_promotion()

No functional change.
Further simplify Bitboards init()

No functional change.
More readable init of MS1BTable[]

Because now it uses lsb(), the BSFTable[] must be
already initialized.

No functional change.
More work on Bitboards::init()

No functional change.
Research at intermediate depth if LMR is very high

After a fail high in LMR, if reduction is very high do
a research at lower depth before teh full depth one.
Chances are that the re-search will fail low and the
full depth one is skipped.

Passed both short TC:
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 11363 W: 2204 L: 2069 D: 7090

And long TC:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 7292 W: 1195 L: 1061 D: 5036

bench: 7869223
Update History and Counter move on TT hit

We already update killers so it is natural to extend to
history and counter move too.

Passed both short TC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 52690 W: 9955 L: 9712 D: 33023

And long TC
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 5555 W: 935 L: 808 D: 3812

bench: 7876473
Sync history and counter moves updating

Change updating rule after a TT hit to match
the same one at the end of the search.

Small change in functionality, but we want to
have uniform rules in the code.

bench: 7767864
Remove threat move stuff

A great simplification that shows no regression
and it seems even a bit scalable.

Tested with fixed number of games:

Short TC
ELO: 0.60 +-2.1 (95%) LOS: 71.1%
Total: 39554 W: 7477 L: 7409 D: 24668

Long TC
ELO: 2.97 +-2.0 (95%) LOS: 99.8%
Total: 36424 W: 5894 L: 5583 D: 24947

bench: 8184352
Reformat Makefile

No functional change.
Further simplify Makefile

No functional change.
Faster and simplified threat eval

Add a bonus according if the attacking
pieces are minor or major.

Passed both short TC
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 13142 W: 2625 L: 2483 D: 8034

And long TC
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 18059 W: 3031 L: 2844 D: 12184

bench: 7425809
Increase pawn king attack weight

Tighter lower bound for pawn attacks so to
activate king safety in some cases like here:

6k1/2B3p1/2Pp1p2/2nPp3/2Q1P2K/P2n1qP1/R6P/1R6 w

Original patch by Chris, further simplified by
Jörg Oster.

Passed both short TC
LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
Total: 30171 W: 5887 L: 5700 D: 18584

And long TC
LLR: 2.97 (-2.94,2.94) [0.00,6.00]
Total: 20706 W: 3402 L: 3204 D: 14100

bench: 7607562
Loosened trigger condition for king safety

Reduce eval discontinuity becuase now we kick in
king safety evaluation in many more cases.

Passed both short TC:
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 8708 W: 1742 L: 1613 D: 5353

And long TC:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 6743 W: 1122 L: 990 D: 4631

bench: 6835416
Bonus for file distance of the outermost pawns

In endgame it's better to have pawns on both wings.
So give a bonus according to file distance between left
and right outermost pawns.

Passed both short TC
LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
Total: 39073 W: 7749 L: 7536 D: 23788

And long TC
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 6149 W: 1040 L: 910 D: 4199

bench: 7665034
Further simplify previous patch

Use a single XOR instead of NEGATE + AND

No functional change.
Fine tune previous patch

Passed short TC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 18331 W: 3608 L: 3453 D: 11270

And scored above 50% on a very long test in long TC
LLR: -2.97 (-2.94,2.94) [0.00,6.00]
Total: 51533 W: 8181 L: 8047 D: 35305

bench: 7335588
Retire MoveImportance[]

Use a skew-logistic function to replace the
MoveImportance[] array.

Verified it does not regress at fixed number
of games both at short TC:
LLR: -2.91 (-2.94,2.94) [-1.50,4.50]
Total: 39457 W: 7539 L: 7538 D: 24380

And long TC:
ELO: -0.49 +-1.9 (95%) LOS: 31.0%
Total: 39358 W: 6135 L: 6190 D: 27033

bench: 7335588
Retire asymmThreshold

Verified with 40K games at long TC does not regress:
ELO: 1.74 +-1.9 (95%) LOS: 96.2%
Total: 39624 W: 6402 L: 6203 D: 27019

bench: 7762310
Remove asymmThreshold stale comment

No functional change.