Merge pull request #1349 from hypothesis/ng-cloak

Use ngCloak to hide UI that isn't ready

h/static/styles/app.scss

@@ -2,6 +2,12 @@
 
 @import 'common';
 
+
+[ng\:cloak], [ng-cloak], [data-ng-cloak], [x-ng-cloak],
+.ng-cloak, .x-ng-cloak {
+  display: none !important;
+}
+
 body {
   @extend .noise;
   font-family: $sansFontFamily;