Arasan 14.2

[jdart]

Arasan 14.2 is available from http://www.arasanchess.org.

Changes in Arasan 14.2:
1) The chess engine handled input from the the UI in several places
and had duplicate code for scanning input and breaking it into lines.
This is now centralized and simplifed.
2) Some other code cleanup, especially conversion from C-style string
handling to C++.
3) Simplified code for lazy eval. Partial (lazy) scores are no longer
cached in the scoring module (such scores were seldom used anyway).
4) Outpost scores reduced.
5) Tweaked threshold values for history pruning and late move pruning (due
to a bug, 14.1 actually did only late move pruning above depth =
1 ply).
6) Reduced thresholds for static null pruning.
7) Some changes to LMR and root move reduction logic.
8) Bug fix: ensure final stage of ply 0 search window widening sets a
correct upper/lower bound.
9) Improvement to logic for searching checks in q-search.
10) Fix material eval adjustment for Q vs 2R.
11) Support is added for varying the engine strength via UCI or Winboard
options (Arasan GUI supports this too).
12) GUI bug fix: search could hang when a "Go" command is issued when it
is the user's turn to move, and the user then makes a manual move before
the search completes.
13) Winboard driver fixes: pings could be processed out of order in some
cases. Also, an extra move could be sent after Winboard has sent a
"resign" or "result" command.

This version is measurably stronger than 14.1 in my testing.

I have also updated the test suite (arasan14.epd), replacing one position (arasan14.167) and adding some new ones (arasan14.176-197).

--Jon