Bring Featured Images back into the main media dialog.

Most users don't realize that the Featured Image meta box exists; if they do, few use it.

Restores the old meta box UI, including the admin_post_thumbnail_html filter. If a plugin is using _wp_post_thumbnail_html() in conjunction with Thickbox elsewhere, it will also magically still work.

Specific underlying changes:
 * Converts the modal view to use the view manager, which means that a call to open() will automatically call render and attach if necessary.
 * Doesn't automatically set a state in wp.media, to allow code to customize the states to be added before activation.

props koopersmith.
fixes #21776.



git-svn-id: http://core.svn.wordpress.org/trunk@22979 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/post.php

@@ -199,14 +199,6 @@ function edit_post( $post_data = null ) {
 			set_post_format( $post_ID, false );
 	}
 
-	// Featured Images
-	if ( isset( $post_data['thumbnail_id'] ) ) {
-		if ( '-1' == $post_data['thumbnail_id'] )
-			delete_post_thumbnail( $post_ID );
-		else
-			set_post_thumbnail( $post_ID, $post_data['thumbnail_id'] );
-	}
-
 	// Meta Stuff
 	if ( isset($post_data['meta']) && $post_data['meta'] ) {
 		foreach ( $post_data['meta'] as $key => $value ) {