Make rounded corners optionnal (but default in gwion)

diff --git a/ast b/ast
index a75405923327ccb7636190044e2b994b26c2a3e7..fc51a3b651dfc788aeafb9dd8668ed691a24ef79 160000 (submodule)
--- a/ast
+++ b/ast
@@ -1 +1 @@
-Subproject commit a75405923327ccb7636190044e2b994b26c2a3e7
+Subproject commit fc51a3b651dfc788aeafb9dd8668ed691a24ef79