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/mixins/has-item-lists.js

@@ -0,0 +1,45 @@
+import Ember from 'ember';
+
+import TaggedArray from 'flarum/utils/tagged-array';
+import ActionButton from 'flarum/components/ui/action-button';
+
+export default Ember.Mixin.create({
+  itemLists: [],
+
+  initItemLists: Ember.on('didInsertElement', function() {
+    var self = this;
+    this.get('itemLists').forEach(function(name) {
+      self.initItemList(name);
+    });
+  }),
+
+  initItemList: function(name) {
+    this.set(name, this.populateItemList(name));
+  },
+
+  populateItemList: function(name) {
+    var items = TaggedArray.create();
+    this.trigger('populate'+name.charAt(0).toUpperCase()+name.slice(1), items);
+    return items;
+  },
+
+  addActionItem: function(items, tag, label, icon, conditionProperty, actionName, actionTarget) {
+    if (conditionProperty && !this.get(conditionProperty)) { return; }
+
+    var self = this;
+    actionTarget = actionTarget || self.get('controller');
+    var item = ActionButton.extend({
+      label: label,
+      icon: icon,
+      action: function() {
+        actionTarget.send(actionName || tag);
+      }
+    });
+
+    var itemInstance = item.create();
+
+    items.pushObjectWithTag(itemInstance, tag);
+
+    return itemInstance;
+  }
+});