Upgrade to Ember 1.11-beta.1

HTMLBars goodness! Since there was some breakage and a lot of fiddling
around to get some things working, I took this opportunity to do a big
cleanup of the whole Ember app. I accidentally worked on some new
features too :3

Note that the app is still broken right now, pending on
https://github.com/emberjs/ember.js/issues/10401

Cleanup:
- Restructuring of components
- Consolidation of some stuff into mixins, cleanup of some APIs that
will be public
- Change all instances of .property() / .observes() / .on() to
Ember.computed() / Ember.observer() / Ember.on() respectively (I think
it is more readable)
- More comments
- Start conforming to a code style (2 spaces for indentation)

New features:
- Post hiding/restoring
- Mark individual discussions as read by clicking
- Clicking on a read discussion jumps to the end
- Mark all discussions as read
- Progressively mark the discussion as read as the page is scrolled
- Unordered list post formatting
- Post permalink popup

Demo once that Ember regression is fixed!

ember/app/components/discussion/post-header/meta.js

@@ -0,0 +1,36 @@
+import Ember from 'ember';
+
+var $ = Ember.$;
+
+/**
+  Component for the meta part of a post header. Displays the time, and when
+  clicked, shows a dropdown containing more information about the post
+  (number, full time, permalink).
+ */
+export default Ember.Component.extend({
+  tagName: 'li',
+  classNames: ['dropdown'],
+  layoutName: 'components/discussion/post-header/time',
+
+  // Construct a permalink by looking up the router in the container, and
+  // using it to generate a link to this post within its discussion.
+  permalink: Ember.computed('post.discusion', 'post.number', function() {
+    var router = this.get('controller').container.lookup('router:main');
+    var path = router.generate('discussion', this.get('post.discussion'), {queryParams: {start: this.get('post.number')}});
+    return window.location.origin+path;
+  }),
+
+  didInsertElement: function() {
+    // When the dropdown menu is shown, select the contents of the permalink
+    // input so that the user can quickly copy the URL.
+    var component = this;
+    this.$('a').click(function() {
+      setTimeout(function() { component.$('.permalink').select(); }, 1);
+    });
+
+    // Prevent clicking on the dropdown menu from closing it.
+    this.$('.dropdown-menu').click(function(e) {
+      e.stopPropagation();
+    });
+  }
+});