Hotfix: 2.4.6

Issue tracker for 2.4.6

- [x] Add clean up script for all the media posts & old `wp_option_tree` table.
- [x] Make sure the plugin will not create multiple media posts ever again!
- [x] Fix strict standards message.
- [x] Add a way to hide the page after the DB is clean and the user implicitly asks.
- [x] Make one last pass over the code to clean up any text and/or naming conventions.
- [x] Allow filtering on the menu and title.
- [x] Final i18n updates.
- [x] Remove paragraph HTML from admin nag.
- [ ] Merge into Master & commit 2.4.6 to the SVN repo.