Tkinter rename, step 2: fix imports and add stub modules.
diff --git a/Lib/idlelib/OutputWindow.py b/Lib/idlelib/OutputWindow.py
index 787e9b0..afc4e39 100644
--- a/Lib/idlelib/OutputWindow.py
+++ b/Lib/idlelib/OutputWindow.py
@@ -1,7 +1,7 @@
-from Tkinter import *
+from tkinter import *
 from EditorWindow import EditorWindow
 import re
-import tkMessageBox
+import tkinter.messagebox as tkMessageBox
 import IOBinding
 
 class OutputWindow(EditorWindow):