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/ui/text-editor.js

@@ -0,0 +1,33 @@
+import Ember from 'ember';
+
+import HasItemLists from 'flarum/mixins/has-item-lists';
+import ActionButton from 'flarum/components/ui/action-button';
+
+/**
+  A text editor. Contains a textarea and an item list of `controls`, including
+  a submit button.
+ */
+export default Ember.Component.extend(HasItemLists, {
+  classNames: ['text-editor'],
+  itemLists: ['controls'],
+
+  value: '',
+  disabled: false,
+
+  didInsertElement: function() {
+    var component = this;
+    this.$('textarea').bind('keydown', 'meta+return', function() {
+      component.send('submit');
+    });
+  },
+
+  populateControls: function(items) {
+    this.addActionItem(items, 'submit', this.get('submitLabel')).set('className', 'btn btn-primary');
+  },
+
+  actions: {
+    submit: function() {
+      this.sendAction('submit', this.get('value'));
+    }
+  }
+});