Twenty Fourteen: revamp the RTL stylesheet and related cleanup. Props iamtakashi, see #25801.

git-svn-id: http://develop.svn.wordpress.org/trunk@25999 602fd350-edb4-49c9-b593-d223f7449a82
Fall back to comment author email in get_avatar() if the user who left the comment no longer exists.

props mauryaratan, lite3.
fixes #25803.

git-svn-id: http://develop.svn.wordpress.org/trunk@26000 602fd350-edb4-49c9-b593-d223f7449a82
Pass comment ID and comment post ID to get_comment_class() in WP_Comments_List_Table::single_row().

props drozdz.
fixes #25814.

git-svn-id: http://develop.svn.wordpress.org/trunk@26001 602fd350-edb4-49c9-b593-d223f7449a82