fix a lot of Tkinter imports
diff --git a/Demo/tkinter/matt/menu-simple.py b/Demo/tkinter/matt/menu-simple.py
index 2487561..a927c50 100644
--- a/Demo/tkinter/matt/menu-simple.py
+++ b/Demo/tkinter/matt/menu-simple.py
@@ -1,4 +1,4 @@
-from Tkinter import *
+from tkinter import *
 
 # some vocabulary to keep from getting confused. This terminology
 # is something I cooked up for this file, but follows the man pages