Switch to latest core (minor update)

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>

diff --git a/core b/core
index 70ee734..3f0fafb 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit 70ee734edd5ebc194feb24c32acb4ed23d055632
+Subproject commit 3f0fafbde81f4dcb8067e4bc5fc7eca57f535ae2