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/routes/discussion.js

@@ -120,6 +120,11 @@ export default Ember.Route.extend({
         .set('paned', true)
         .set('paneShowing', false);
       this.controllerFor('composer').send('minimize');
+
+      var application = this.controllerFor('application');
+      if (!application.get('backButtonTarget')) {
+        application.set('backButtonTarget', this.controllerFor('index'));
+      }
     }
   }
 });