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/application/user-dropdown.js

@@ -0,0 +1,27 @@
+import Ember from 'ember';
+
+import HasItemLists from 'flarum/mixins/has-item-lists';
+import DropdownButton from 'flarum/components/ui/dropdown-button';
+import SeparatorItem from 'flarum/components/ui/separator-item';
+
+export default DropdownButton.extend(HasItemLists, {
+  layoutName: 'components/application/user-dropdown',
+  itemLists: ['items'],
+
+  buttonClass: 'btn btn-default btn-naked btn-rounded btn-user',
+  menuClass: 'pull-right',
+  label: Ember.computed.alias('user.username'),
+
+  populateItems: function(items) {
+    this.addActionItem(items, 'profile', 'Profile', 'user');
+    this.addActionItem(items, 'settings', 'Settings', 'cog');
+    items.pushObject(SeparatorItem.create());
+    this.addActionItem(items, 'logout', 'Log Out', 'sign-out', null, null, this);
+  },
+
+  actions: {
+    logout: function() {
+      this.logout();
+    }
+  }
+})