Fix Jasmine test failure after bf76894f

Sequence content does not double-escaped anymore, and eval() usage was
also removed from the sequence module.

static/coffee/fixtures/items.json

 [
   {
-    "content": "\"Video 1\"",
+    "content": "Video 1",
     "type": "video",
     "title": "Video 1"
   }, {
-    "content": "\"Video 2\"",
+    "content": "Video 2",
     "type": "video",
     "title": "Video 2"
   }, {
-    "content": "\"Sample Problem\"",
+    "content": "Sample Problem",
     "type": "problem",
     "title": "Sample Problem"
   }

static/coffee/src/modules/tab.coffee

@@ -16,7 +16,7 @@ class @Tab
 
   onShow: (element, ui) =>
     @$('section.ui-tabs-hide').html('')
-    @$("##{@tabId(ui.index)}").html(eval(@items[ui.index]['content']))
+    @$("##{@tabId(ui.index)}").html(@items[ui.index]['content'])
     @element.trigger 'contentChanged'
 
   tabId: (index) ->