Update core.

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

diff --git a/core b/core
index ab6d7d8..1f16638 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit ab6d7d83467fc5e19755550d36144b26a9a29fb7
+Subproject commit 1f16638f53b3521f838ce7cdb341c2332e4a046d