fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/canvasevents.py b/Demo/tkinter/guido/canvasevents.py
index 74ed76f..aeb0eb1 100644
--- a/Demo/tkinter/guido/canvasevents.py
+++ b/Demo/tkinter/guido/canvasevents.py
@@ -1,6 +1,6 @@
 #! /usr/bin/env python
 
-from Tkinter import *
+from tkinter import *
 from Canvas import Oval, Group, CanvasText