fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/hanoi.py b/Demo/tkinter/guido/hanoi.py
index 58ba1d1..a29b1d7 100755
--- a/Demo/tkinter/guido/hanoi.py
+++ b/Demo/tkinter/guido/hanoi.py
@@ -10,7 +10,7 @@
 # background of the animation.  Default is no bitmap.
 
 # This uses Steen Lumholt's Tk interface
-from Tkinter import *
+from tkinter import *
 
 
 # Basic Towers-of-Hanoi algorithm: move n pieces from a to b, using c