[Retros] Version 3.3 of Natch is available

[Pascal Wassong]

Hello all,

I have created version 3.3 of Natch.  It corrects a bug found and
thoroughly analysed by Mark Watkins.

The bug happened for example in the following position, where two pieces
block the same line, here f8-a3, and another piece could have a shorter
trajectory if the line were not blocked (here Qd8-e7-a3).  After the
move bBf8-e7, the block by bPe7-d6 was no more found and the bQ could
then reach a3 in 2 moves, instead of 3 previously.  This spare coming
out of nothing did that no solution was found.  It could probably also
happen on a column, eg h2-h4 and Rh1-h2, but I have not testing that.

This bug was probably introduced in version 2.5Beta, dated from 2009.

The new version is available at the usual place: http://Natch.free.fr

A big thank you to Mark Watkins.

Courage and patience,
Pascal

+---+---+---+---+---+---+---+---+
|*R |*N |*B | . |*K | . |*N | . |
+---+---+---+---+---+---+---+---+
|*P |*P |*P |*P |*B |*P |*P |*R |
+---+---+---+---+---+---+---+---+
|   | . |   |*P |   | . |   |*P |
+---+---+---+---+---+---+---+---+
| P |   | . |   | . |   | . |   |
+---+---+---+---+---+---+---+---+
|   | R |   | . |   | . |   | . |
+---+---+---+---+---+---+---+---+
|*Q |   | . | P | . |   | . |   |
+---+---+---+---+---+---+---+---+
|   | P | P | . | P | P | P | P |
+---+---+---+---+---+---+---+---+
| . | N | . | Q | K | B | N | R |
+---+---+---+---+---+---+---+---+'
rnb1k1n1/ppppbppr/3p3p/P7/1R6/q2P4/1PP1PPPP/1N1QKBNR
14 single moves.	15 + 16