Post Cloaking:

* We now use a new custom view, {{cloaked-collection}} to display posts in a topic.

* Posts are removed and inserted (cloaked/uncloaked) into the DOM dynamically based on whether they
  are visible in the current browser viewport.

* There's been a lot of refactoring to ensure the relationship between the post views and the topic
  controller is sane.

* Lots of fixes involving jumping to a post, including a new LockOn component to that tries to stay
  focused on an element even if stuff is loading before it in the DOM that would normally push it
  down.

test/javascripts/integration/view_topic_test.js

@@ -5,6 +5,6 @@ test("Enter a Topic", function() {
 
   visit("/t/internationalization-localization/280").then(function() {
     ok(exists("#topic"), "The was rendered");
-    ok(exists("#topic .topic-post"), "The topic has posts");
+    ok(exists("#topic .post-cloak"), "The topic has cloaked posts");
   });
 });