fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/solitaire.py b/Demo/tkinter/guido/solitaire.py
index a521c66..b2a2a66 100755
--- a/Demo/tkinter/guido/solitaire.py
+++ b/Demo/tkinter/guido/solitaire.py
@@ -25,7 +25,7 @@
 import math
 import random
 
-from Tkinter import *
+from tkinter import *
 from Canvas import Rectangle, CanvasText, Group, Window