Revert "When updating the viewer, don't change the route"

This reverts commit 32f307074f8be09dd1fd853dac1afa432076dfeb.

Fixes #794.
Reopens #790.

h/js/services.coffee

@@ -300,6 +300,7 @@ class Hypothesis extends Annotator
       ($location, $rootScope) =>
         @buildReplyList annotations
         $rootScope.annotations = annotations
+        $location.path('/viewer').replace()
         $rootScope.$digest()
     ]
     this