Make drag/drop save content immediately in seqs and verticals

common/lib/xmodule/xmodule/js/src/sequence/edit.coffee

@@ -1,4 +1,9 @@
 class @SequenceDescriptor extends XModule.Descriptor
   constructor: (@element) ->
     @$tabs = $(@element).find("#sequence-list")
-    @$tabs.sortable()
+    @$tabs.sortable(
+      update: (event, ui) => @update()
+    )
+
+  save: ->
+    children: $('#sequence-list li a', @element).map((idx, el) -> $(el).data('id')).toArray()

common/lib/xmodule/xmodule/js/src/vertical/edit.coffee

@@ -1,4 +1,9 @@
 class @VerticalDescriptor extends XModule.Descriptor
   constructor: (@element) ->
     @$items = $(@element).find(".vert-mod")
-    @$items.sortable()
+    @$items.sortable(
+      update: (event, ui) => @update()
+    )
+
+  save: ->
+    children: $('.vert-mod li', @element).map((idx, el) -> $(el).data('id')).toArray()

common/lib/xmodule/xmodule/vertical_module.py

@@ -17,7 +17,10 @@ class VerticalModule(XModule):
 
     def get_html(self):
         if self.contents is None:
-            self.contents = [child.get_html() for child in self.get_display_items()]
+            self.contents = [{
+                'id': child.id,
+                'content': child.get_html()
+            } for child in self.get_display_items()]
 
         return self.system.render_template('vert_module.html', {
             'items': self.contents