Add an .html4-captions class to the editor when HTML5 captions are not supported, for theme use.

see #26642.


git-svn-id: https://develop.svn.wordpress.org/trunk@27758 602fd350-edb4-49c9-b593-d223f7449a82
Fix double avatars and JS errors when spamming/trashing comments.

Props avryl, SergeyBiryukov.
Fixes #27329.
 


git-svn-id: https://develop.svn.wordpress.org/trunk@27759 602fd350-edb4-49c9-b593-d223f7449a82