* Scroll all content, rather than the dual-pane scrolling awkwardness.
* Better align the header image and title overlay with the display on WordPress.org, at least at full-width.
* Move the close button outside of the modal itself, rather than overlay on top of colors we can't predict.
props stephdau, tellyworth, helen. fixes#27440.
git-svn-id: https://develop.svn.wordpress.org/trunk@29474 602fd350-edb4-49c9-b593-d223f7449a82