Updated to work with WP version 3.9.1

* Updated the way the plugin searches for the right slot ID to use with the publisher ID. Now users can have the same publisher ID and different slot ID's.
* Fixed the widget so it works.
* Updated the link to the advert places.
* Updated all the URL's and email addresses.
* Fixed the undefined variables messages.

git-svn-id: https://plugins.svn.wordpress.org/author-advertising-plugin/trunk@918977 b8457f37-d9ea-0310-8a92-e5e31aec5664