Add the missing __main__.py in the turtledemo package.  It seems to have been lost during some mass rename action (r86095).
diff --git a/Lib/turtledemo/about_turtledemo.txt b/Lib/turtledemo/about_turtledemo.txt
index 54c25a5..a9009bd 100644
--- a/Lib/turtledemo/about_turtledemo.txt
+++ b/Lib/turtledemo/about_turtledemo.txt
@@ -1,9 +1,9 @@
 
     --------------------------------------
-        About turtleDemo.py
+        About this viewer
     --------------------------------------
 
-    Tiny demo Viewer to view turtle graphics example scripts.
+    Tiny demo viewer to view turtle graphics example scripts.
 
     Quickly and dirtyly assembled by Gregor Lingl.
     June, 2006