Remove note about Playdoh from CONTRIBUTING.md

All open pull requests were submitted after the Playdoh upgrade.

CONTRIBUTING.md

@@ -7,14 +7,3 @@ docs have a lot of information about how to get your local environment setup
 for development, as well as how to format your code and commit messages.
 Following these guidelines will very much increase the chances of a pleasant
 code-review experience.
-
-# NEWS
-
-## HUGE PROJECT STRUCTURE CHANGE
-
-On May 15th, 2013 we updated the site to the latest
-[Playdoh](http://playdoh.readthedocs.org/). This is a large change, so your local
-environment will need some updating, and if you submitted a pull-request prior to
-the merge it will need a rebase. Please check the
-[bedrock docs](bedrock.readthedocs.org/en/latest/install.html#upgrading) for
-details.