Use last core.

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

diff --git a/core b/core
index a7f778a..e25ddad 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit a7f778a593a0a7e168a7112ec28cb84d032adaf3
+Subproject commit e25ddad9784ef9e8e4de1847b50207f88622a165