Bug Fix for Book Collections

[mishawagon]

Hello,

There seems to be a small bug in the book collections code. Here is the diff that fixed it. I tried to commit and push the change, but was denied with a 403. Anyway, thank you for these great examples!

--- a/examples/books_collection/collection/forms.py
+++ b/examples/books_collection/collection/forms.py
@@ -4,7 +4,7 @@

Use of this source code is governed by a BSD-style

license that can be found in the LICENSE file.

-from flaskext import wtf
+from flask.ext import wtf