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-input.js

@@ -0,0 +1,26 @@
+import Ember from 'ember';
+
+/**
+  An extension of Ember's text field with an option to set up an auto-growing
+  text input.
+ */
+export default Ember.TextField.extend({
+  autoGrow: false,
+
+	didInsertElement: function() {
+    if (this.get('autoGrow')) {
+  		var component = this;
+  		this.$().on('input', function() {
+  			var empty = !$(this).val();
+  			if (empty) {
+  				$(this).val(component.get('placeholder'));
+  			}
+  			$(this).css('width', 0);
+  			$(this).width($(this)[0].scrollWidth);
+  			if (empty) {
+  				$(this).val('');
+  			}
+  		});
+    }
+	}
+});