small refactoring

--HG--
branch : trunk
diff --git a/jinja2/nodes.py b/jinja2/nodes.py
index 1f742fa..960a540 100644
--- a/jinja2/nodes.py
+++ b/jinja2/nodes.py
@@ -800,5 +800,13 @@
         return Markup(self.expr.as_const())
 
 
+class Continue(Stmt):
+    """Continue a loop."""
+
+
+class Break(Stmt):
+    """Break a loop."""
+
+
 # and close down
 _node_setup_finished = True