* Support a `caption` attribute for audio and video shortcodes
* In `wp.media.audio|video`, rename `update` to `shortcode` to allow these models to share the same mixins as `wp.media.collection` subclasses
* When sending an audio or video shortcode to the editor, create a default caption if the user hasn't entered one. This currently only displays in the editor, not on the front end. Captions aren't tied to a specific attachment here because external sources are supported.
* In the `wp.mce.media` mixin, in the `edit` method, read `attr` instead of `data` when attempting to parse the encoded shortcode. `data` does not automatically update when the attribute changes. This was a blessing to debug.
* Add `wp.mce.media.PlaylistView` to support playlist views in TinyMCE
* Expose `WPPlaylistView` to global scope and suppress auto-parsing of playlist nodes when in the admin. Allow `WPPlaylistView` to be passed `metadata` on creation instead of requiring a JSON blob to be parsed.
* Remove all of the playlist logic from the `wpgallery` TinyMCE plugin.
* In `wp_prepare_attachment_for_js()` return more data for audio/video so that playlists can have parity in the admin/front end.
See #27320.
Built from https://develop.svn.wordpress.org/trunk@27640
git-svn-id: http://core.svn.wordpress.org/trunk@27483 1a063a9b-81f0-0310-95a4-ce76da25c4cd
* Playlists operate like galleries in the admin.
* Provide default UI and JS support in themes using MediaElement and Backbone.
* The shortcodes are clickable, editable, and configurable using the media modal.
* Playlists support images for each item, whether or not the current theme supports images for `attachment:audio` and `attachment:video`
* Playlists respond to `$content_width` and resize videos accordingly.
* All playlist data is included inline, using a script tag with `type="application/json"`, allowing anyone to unenqueue the WP playlist JS and roll their own.
* Playlist styles are minimal and work out of the box in the last 5 default themes. They inherit and adapt to the current theme's font styles, and their rules are easily overrideable.
See #26631.
Built from https://develop.svn.wordpress.org/trunk@27239
git-svn-id: http://core.svn.wordpress.org/trunk@27096 1a063a9b-81f0-0310-95a4-ce76da25c4cd
