Media Grid/Modal Keyboard navigation improvements:

* Add focus to arrows on Next/Previous in the grid's modal on left/right keypress, and add the necessary CSS for `:focus`
* When in a disabled input in the grid modal, allow the left/right keys to work
* Make the image editor return a `$.Deferred` so that there isn't a race condition with UI loading. 
* Assign focus when the edit image mode is rendered so that the modal can be closed on Esc press

Props wonderboymusic, adamsilverstein (for the initial patch).
See #23560.

Built from https://develop.svn.wordpress.org/trunk@29560


git-svn-id: http://core.svn.wordpress.org/trunk@29335 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/image-edit.js

@@ -302,7 +302,7 @@ var imageEdit = window.imageEdit = {
 	open : function( postid, nonce, view ) {
 		this._view = view;
 
-		var data, elem = $('#image-editor-' + postid), head = $('#media-head-' + postid),
+		var dfd, data, elem = $('#image-editor-' + postid), head = $('#media-head-' + postid),
 			btn = $('#imgedit-open-btn-' + postid), spin = btn.siblings('.spinner');
 
 		btn.prop('disabled', true);
@@ -315,13 +315,20 @@ var imageEdit = window.imageEdit = {
 			'do': 'open'
 		};
 
-		elem.load(ajaxurl, data, function() {
+		dfd = $.ajax({
+			url:  ajaxurl,
+			type: 'post',
+			data: data
+		}).done(function( html ) {
+			elem.html( html );
 			head.fadeOut('fast', function(){
 				elem.fadeIn('fast');
 				btn.removeAttr('disabled');
 				spin.hide();
 			});
 		});
+
+		return dfd;
 	},
 
 	imgLoaded : function(postid) {