Media: Integrate the gallery workflow with the media menu.

`wp.media.model.Query.more()`
* If a request has already been sent out for more attachments, return that request object instead of creating another.

`wp.media.controller.Region`
* A region allows views to be swapped in and out of a section of the page without either view having to know about the other.
* Application components can use the same callbacks and resources by leveraging `Region.mode()`, which triggers a set of callbacks to create or transform the current view, but only if necessary.

`wp.media.view.Frame`
* Leverage `Region` controllers instead of forcing states to swap view objects, which causes states to fit more comfortably in the controller-camp.
* Add `previous()`, a method to fetch the previous state `id`.
* Separate out the default settings over several objects (so blank frames can be instantiated).

`wp.media.view.MediaFrame`
* The base `Frame` used for media management: handles integration with the `Modal` and `UploaderWindow` views.

`wp.media.view.MediaFrame.Post`
* Includes all default media states and callbacks necessary for inserting media into a post.

see #21390.


git-svn-id: https://develop.svn.wordpress.org/trunk@22437 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/script-loader.php

@@ -330,8 +330,9 @@ function wp_default_scripts( &$scripts ) {
 		'selected'    => __( 'selected' ),
 
 		// Upload
-		'uploadFilesTitle' => __( 'Upload Files' ),
-		'selectFiles'      => __( 'Select files' ),
+		'uploadFilesTitle'  => __( 'Upload Files' ),
+		'selectFiles'       => __( 'Select files' ),
+		'uploadImagesTitle' => __( 'Upload Images' ),
 
 		// Library
 		'mediaLibraryTitle' => __( 'Media Library' ),
@@ -342,8 +343,14 @@ function wp_default_scripts( &$scripts ) {
 		// Embed
 		'embedFromUrlTitle' => __( 'Embed From URL' ),
 
+		// Batch
+		'batchInsert'      => __( 'Batch insert' ),
+		'cancelBatchTitle' => __( '← Cancel Batch' ),
+
 		// Gallery
 		'createGalleryTitle' => __( 'Create Gallery' ),
+		'editGalleryTitle'   => __( 'Edit Gallery' ),
+		'cancelGalleryTitle' => __( '← Cancel Gallery' ),
 		'insertGallery'      => __( 'Insert gallery' ),
 		'updateGallery'      => __( 'Update gallery' ),
 		'continueEditing'    => __( 'Continue editing' ),