* Videos should always render at the same aspect ratio.
* Don't force a pseudo-mime-type for `.m4v` files
* Uniformly adapt to `$content_width` when setting video dimensions on the front end
* Add the `height` attribute to the initial `<video>` in the video playlist JS template
* Add some defensive/responsive CSS for a/v on the Edit Media page

See #27243.


Built from https://develop.svn.wordpress.org/trunk@27328


git-svn-id: http://core.svn.wordpress.org/trunk@27180 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add some missing number i18n in `Walker_Category` and `Walker_CategoryDropdown`. Fixes #22745.
Built from https://develop.svn.wordpress.org/trunk@27329


git-svn-id: http://core.svn.wordpress.org/trunk@27181 1a063a9b-81f0-0310-95a4-ce76da25c4cd
in TwentyFourteen: don't add the `has-post-thumbnail` class or print the featured image when viewing an attachment.

See #27243.


Built from https://develop.svn.wordpress.org/trunk@27330


git-svn-id: http://core.svn.wordpress.org/trunk@27182 1a063a9b-81f0-0310-95a4-ce76da25c4cd