Use last version of the core.

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

diff --git a/core b/core
index a794b0b..e94c4a1 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit a794b0bd619df7b333018eb8435f755032ea4e8b
+Subproject commit e94c4a1713cc0d63508a5d0ecd2d572f047975fb