Tkinter rename, step 2: fix imports and add stub modules.
diff --git a/Lib/idlelib/ScriptBinding.py b/Lib/idlelib/ScriptBinding.py
index cb01110..c6892f3 100644
--- a/Lib/idlelib/ScriptBinding.py
+++ b/Lib/idlelib/ScriptBinding.py
@@ -22,7 +22,7 @@
 import string
 import tabnanny
 import tokenize
-import tkMessageBox
+import tkinter.messagebox as tkMessageBox
 import PyShell
 
 from configHandler import idleConf