Bug #23, Updates to "ou-attribution" WordPress plugin

* 4th Gist revision: https://gist.github.com/nfreear/56d6f4a76413fb7a4ae4
* @https://github.com/mhawksey/wp-evidence-hub/issues/12
Bug #23, Big extensions to "ou-attribution" plugin - copyright, license

* https://github.com/mhawksey/wp-evidence-hub/issues/12