Mobile Responsive Styles (#580)

* WIP: Responsive styles

* Flip breakpoints, ensure doc doesn't spread

* Add MenuIcon

* Refactor Sidebar to share mobile responsive styles

* Fix accidental find/replace

* Tweak padding to take into account icon spacing

app/components/Toasts/components/Toast.js

@@ -33,7 +33,11 @@ class Toast extends Component {
   }
 
   render() {
-    const { type, onRequestClose, message } = this.props;
+    const { type, onRequestClose } = this.props;
+    const message =
+      typeof this.props.message === 'string'
+        ? this.props.message
+        : this.props.message.toString();
 
     return (
       <Container onClick={onRequestClose} type={type}>