Switch to core v1.1.9

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

diff --git a/core b/core
index f6cfa61..1256fe0 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit f6cfa61b4536e3a823508febe97317736dc16074
+Subproject commit 1256fe0522a97b7a8ed8a1e12a22378cb6503fbc