Update libtcod to v1.6.6

HexDecimal · HexDecimal · commit 376cc5676db9 · 2018-04-07T09:47:05.000-07:00
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -7,6 +7,11 @@ here.
 This project adheres to `Semantic Versioning <https://semver.org/>`_ since
 v2.0.0
 
+Unreleased
+------------------
+Changed
+ - Updated libtcod to v1.6.6
+
 4.3.2 - 2018-03-18
 ------------------
 Deprecated
diff --git a/libtcod b/libtcod
@@ -1 +1 @@
-Subproject commit 025e26b0260bc9a6ce6132913d9f5031a4b3311b
+Subproject commit 667d9c7be20517d5c0d7b858e19d9695e1439023
