Tkinter rename, step 2: fix imports and add stub modules.
diff --git a/Lib/idlelib/StackViewer.py b/Lib/idlelib/StackViewer.py
index 6b7730b..794726d 100644
--- a/Lib/idlelib/StackViewer.py
+++ b/Lib/idlelib/StackViewer.py
@@ -7,7 +7,7 @@
 
 def StackBrowser(root, flist=None, tb=None, top=None):
     if top is None:
-        from Tkinter import Toplevel
+        from tkinter import Toplevel
         top = Toplevel(root)
     sc = ScrolledCanvas(top, bg="white", highlightthickness=0)
     sc.frame.pack(expand=1, fill="both")
@@ -128,7 +128,7 @@
         reload(testcode)
     except:
         sys.last_type, sys.last_value, sys.last_traceback = sys.exc_info()
-    from Tkinter import Tk
+    from tkinter import Tk
     root = Tk()
     StackBrowser(None, top=root)
     root.mainloop()