Make sure that the ID of the right revision is not less than the ID of the left revision

see #23497

git-svn-id: http://core.svn.wordpress.org/trunk@23832 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23833.

git-svn-id: http://core.svn.wordpress.org/trunk@23833 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Kill the HR on revisions page. see #23497

git-svn-id: http://core.svn.wordpress.org/trunk@23834 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: style native `mediaelement` video player with a black background color. Props obenland, closes #23821.

git-svn-id: http://core.svn.wordpress.org/trunk@23835 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Rename the_extra_content() to the_remaining_content().

fixes #23877.

git-svn-id: http://core.svn.wordpress.org/trunk@23836 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: better back compat handling by moving version compare before the include to avoid loading the file altogether. Also prevent Customizer views. Props obenland, closes #23819.

git-svn-id: http://core.svn.wordpress.org/trunk@23837 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: back compat file PHPDoc updates, thanks DrewAPicture for the nudge. See #23819.

git-svn-id: http://core.svn.wordpress.org/trunk@23838 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: improvements to Image post format handling to use a custom image size instead of filtering a `$content_width` variable.

Includes CSS cleanup and markup improvements to both video and image templates, moving the media HTML piece out of the `header` element.

Props obenland, closes #23620.

git-svn-id: http://core.svn.wordpress.org/trunk@23839 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Move the "look for the first media attachment" code below the "look
in the post content for media" code, so that it is the method of last
resort. This way, if you attach AND embed media, you won't get duplication.

fixes #23879

git-svn-id: http://core.svn.wordpress.org/trunk@23840 1a063a9b-81f0-0310-95a4-ce76da25c4cd