Responsive design baby!

Mobile responsive design with a very native feel, all in pure CSS (no
templating differences between versions — even though some things are
in very different positions.)

I’ve been working on this whole thing in my head for a while now,
planning out how certain components will be laid out on the mobile
version, and how to reason about them in the templates so that a
substantially different layout can still be achieved by only using CSS.
Today I finally wrote the CSS and it’s come together pretty damn
perfectly.

Still to come:
- Swiping left or right on discussions to reveal controls
- Tablet version

ember/app/components/application/back-button.js

@@ -5,7 +5,7 @@ import Ember from 'ember';
  */
 export default Ember.Component.extend({
   classNames: ['back-button'],
-  classNameBindings: ['active'],
+  classNameBindings: ['active', 'className'],
 
   active: Ember.computed.or('target.paneIsShowing', 'target.paneIsPinned'),
 
@@ -25,6 +25,10 @@ export default Ember.Component.extend({
 
     togglePinned: function() {
       this.get('target').send('togglePinned');
+    },
+
+    toggleDrawer: function() {
+      this.sendAction('toggleDrawer');
     }
   }
 });