Move the Mediaelement.js include into the wp-includes/js folder, rather than wp-includes directly. Fixes the mediaplayer in browsers which don't support <audio> directly.
Props DrewAPicture See #23282.


git-svn-id: https://core.svn.wordpress.org/trunk@23732 1a063a9b-81f0-0310-95a4-ce76da25c4cd