Use last version of the core-lib.

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

diff --git a/core b/core
index ca47693..a794b0b 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit ca476935c2eed1151b14a783f2ca404218ebfae4
+Subproject commit a794b0bd619df7b333018eb8435f755032ea4e8b