Updates core to latest version.

Signed-off-by: Vincent Zanotti <vincent.zanotti@polytechnique.org>

diff --git a/core b/core
index 9ddc36c..5177a1b 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit 9ddc36c19f494568e806b7a445074ef80640d467
+Subproject commit 5177a1b50e47e7d62a66aba9565580af3abf15dd