Merge pull request #3007 from edx/frances/feature/ui-loading

added loading pattern to studio

cms/templates/ux/reference/container.html

@@ -35,6 +35,11 @@ from django.core.urlresolvers import reverse
     <div class="inner-wrapper">
         <section class="content-area">
             <article class="content-primary">
+
+            <div class="ui-loading">
+                <p><span class="spin"><i class="icon-refresh"></i></span> <span class="copy">Loading...</span></p>
+            </div>
+
                 <section class="wrapper-xblock level-page">
                     <header class="xblock-header">
                         <div class="header-details">