[Effen] Add a README.txt file that describes how to test Effen using the stock app.

Also includes a link to all the know bugs that affect the stock app.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1145523003

examples/stocks/README.md

+This sample app is our main test harness right now.
+
+Follow these steps to make sure everything works, comparing the
+results to earlier builds:
+
+ 1. Load the app
+ 2. Scroll down and up.
+ 3. Fling down.
+ 4. Fling up. Verify that it bounces at the top.
+ 5. Tap on rows. Make sure they get ink splashes.
+ 6. Open the drawer.
+ 7. Slide the drawer in and out.
+ 8. Check that you can change the radio buttons.
+ 9. Check for ink splashes on each row but not in the header.
+10. Check that you can't scroll the list with the drawer out.
+11. Close the drawer.
+12. Open the menu.
+13. Check the checkbox.
+14. Open the menu. Verify the checkbox is checked.
+15. Tap another menu item.
+16. Hit search.
+17. Type a query like "XXI".
+18. Dismiss the keyboard.
+19. Scroll the list. Verify that you can't overscroll.
+20. Tap the search bar. Verify the keyboard comes back.
+21. Switch to the voice keyboard. Verify that that keyboard works.
+22. Hit the back button.
+23. Verify that the floating action button gets ink splashes.
+
+These steps carefully avoid known bugs. See:
+   https://github.com/domokit/mojo/labels/stock%20demo