fix bug in capstone -> wall logicHEADmain

From: ~devp

Previously, the cap flag checked stone 0 of a stack rather than stone
n-1, so it did not take into account a capstone moved as part of a
stack. I additionally added logic to check that no other stones were
dropped with the capstones, per Tak rules.

1 files changed, 6 insertions, 0 deletions

diff --git a/README.md b/README.md
index a01db3f..4830c94 100644
--- a/README.md
+++ b/README.md
@@ -49,3 +49,9 @@ for this purpose.
 Note that the engine is expected to respect the `[Variant XXX]` line
 in the PTN game-state, so expect breakage with anything but the
 default.
+
+## Additional contributors
+
+With thanks to
+
+- ~devp for fixing a capstone->wall flattening bug