Update core

Signed-off-by: Vincent Zanotti <vincent.zanotti@m4x.org>

diff --git a/core b/core
index d7dd3bd..2b1ac5a 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit d7dd3bd88b07c6b49c48fd90ab741de025978177
+Subproject commit 2b1ac5abd3eafffdc01beb88a90ca0ba88c6ad18