Gallery preview: add a "No items found" state which is displayed when rendering the gallery wpview and no attachments are found. Props gcorne, fixes #27558
Built from https://develop.svn.wordpress.org/trunk@27899


git-svn-id: http://core.svn.wordpress.org/trunk@27730 1a063a9b-81f0-0310-95a4-ce76da25c4cd
wpLink: fix spinners selectors and add some throttling when searching with AJAX while the user is typing, fixes #27615
Built from https://develop.svn.wordpress.org/trunk@27900


git-svn-id: http://core.svn.wordpress.org/trunk@27731 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Drag and drop files on the editor to upload: add new argument to wp_editor() to enable, fixes #27465
Built from https://develop.svn.wordpress.org/trunk@27901


git-svn-id: http://core.svn.wordpress.org/trunk@27732 1a063a9b-81f0-0310-95a4-ce76da25c4cd