fix a lot of Tkinter imports
diff --git a/Demo/tkinter/matt/placer-simple.py b/Demo/tkinter/matt/placer-simple.py
index 992a8fc..6be0de9 100644
--- a/Demo/tkinter/matt/placer-simple.py
+++ b/Demo/tkinter/matt/placer-simple.py
@@ -1,4 +1,4 @@
-from Tkinter import *
+from tkinter import *
 
 # This is a program that tests the placer geom manager