Use last core.

Signed-off-by: Florent Bruneau <florent.bruneau@polytechnique.org>

diff --git a/core b/core
index 6cc34b5..eec9962 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit 6cc34b5041e235805e37756b146b86a62f104e2a
+Subproject commit eec996233a443d9d024786583c0370a54d639dde