Adding data_change to use to signal to Screenful that save button nedds a litle star

src/lib/screenful.py

@@ -0,0 +1,15 @@
+from browser import window
+# interface to screenful
+
+class ScreenfulEmptyShell:
+    def __init__(self):
+        func = lambda: None
+        self.Editor = {"changed": func}
+        
+def screenful():
+    return window.Screenful if window.Screenful else ScreenfulEmptyShell()
+            
+            
+def changed():
+    console.log(Screenful, window.Screenful)
+    screenful().Editor.changed();