Return static eval when reaching MAX_PLY

Makes more sense than returning a draw score. Tested
with reduced MAX_PLY = 30 and passed both short TC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 17434 W: 3345 L: 3194 D: 10895

And long TC
LLR: 2.97 (-2.94,2.94) [0.00,6.00]
Total: 2610 W: 488 L: 373 D: 1749

With current limit of MAX_PLY = 100 the patch should not
introduce any measurable change, nevertheless is the correct
approach.

Idea of returning eval is from  Michel Van den Bergh.

bench: 8430785
Assorted renaming in search

Inspired by DON.

No functional change.
Rename ProbCut to Multicut

The teqnique used is actually MultiCut:

https://chessprogramming.wikispaces.com/Multi-Cut

And not ProbCut:

https://chessprogramming.wikispaces.com/ProbCut

No functional change.
Reformat of eval tracing code

Also assorted rename while there.

No functional change.
Restore PorbCut name

Actually MultiCut is too different from current scheme.
Note that neither ProbCut is exactly what we do because
we try just a handful of captures instead of all moves,
nevertheless it seems more in line with what we do.

Suggested by Joona.

No functional change.
Fix material key for King

Currently king has no material key associated because
it can never happen to find a legal position without
both kings, so there is no need to keep track of it.

The consequence is that a position with only the two
kings has material key set at zero and if the material
hash table is empty any entry will match and this is
wrong.

Normally bug is hidden becuase the checking for a draw
with pos.is_draw() is done earlier than evaluate() call,
so that we never check in gameplay the material key of a
position with two kings.

Nevertheless the bug is there and can be reproduced setting
at startup a position with only two kings and typing
'eval' from prompt.

The fix is very simple: add a random key also for the king.

Also fixed the condition in material.cpp to avoid asserting
when a 'just 2 kings' postion is evaluated.

No functional change.
Increase MAX_PLY from 100 to 120

Under some very rare case 100 plies of search
could be not enough. Increasing more could lead
to crashes due to reached stack size limit on
some platforms.

Strongly requested by Uri.

bench: 8430785
Sync code style in material.cpp

Update to use common code style.

No functional change.
Update SEE to return a Value

It seems more natural because the actual returned
value is from PieceValue[] array.

No functional change.
Don't update pieceCount for ALL_PIECES

It is currently unused and only adds
overhead for nothing.

Also set proper type of chess960.

No functional change.
Avoid recalculating CheckInfo in generate_castling()

No functional change.
Distribute part of first move time to other moves

Passed both short TC:
LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
Total: 18907 W: 3475 L: 3322 D: 12110

And long TC:
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 19044 W: 2997 L: 2811 D: 13236

bench: 8430785
Fix an assert in Probcut

When running the following position:

8/kPp5/2P3p1/p1P1p1P1/2PpPp2/3p1p2/3P1P2/5K2 w - - 0 1

An assert is raised at depth 92:

assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);

This is because it happens that beta = 29832,
so rbeta = 30032 that is > VALUE_INFINITE

Bug spotted and analyzed by Uri, fix suggested by Joerg.

Other fixes where possible but this one is pointed
exactly at the source of the bug, so it is the best
from a code documentation point of view.

bench: 8430785
Fix a warning with Intel compiler

warning #2259: non-pointer conversion from "int" to
"uint8_t={unsigned char}" may lose significant bits

No functional change
Dynamic draw value

Try to avoid repetition draws at early midgame,
this should give an edge against weaker opponents
and reduce draw rate.

Tested for regressions with SPRT[-3, 1] and
passed both short TC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 68498 W: 12928 L: 12891 D: 42679

And long TC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 40212 W: 6386 L: 6295 D: 27531

bench: 7990513
Retire UCI_AnalyseMode option

It has been obsoleted out already some time ago
and currently there is no point in changing eval
score according to if we are in game or analyzing.

So retire the option.

No functional change.
Simplify Bitboards::pretty

No functional change.
Rename xxx_to_char() -> to_char()

No functional change.
Remove limit of minimumSplitDepth

There is no reason why an user cannot set
it at a value less than 4.

No functional change.
Pass CastlingFlag argument only

Instead of Color and CastlingSide. Change functions API
accordingly.

No functional change.