fix a lot of Tkinter imports
diff --git a/Demo/tkinter/matt/slider-demo-1.py b/Demo/tkinter/matt/slider-demo-1.py
index 5662db9..687f8a3 100644
--- a/Demo/tkinter/matt/slider-demo-1.py
+++ b/Demo/tkinter/matt/slider-demo-1.py
@@ -1,4 +1,4 @@
-from Tkinter import *
+from tkinter import *
 
 # shows how to make a slider, set and get its value under program control