angular.module('app', ['ngRoute']).
  config(function($routeProvider, $locationProvider) {
    $locationProvider.html5Mode(false).hashPrefix("!");
    $routeProvider.
      when("/hello_world", {
        templateUrl: "templates/hello_world.html"
      }).
      otherwise("/hello_world");
  });

@@ -173,27 +173,16 @@
  when(%22/
-hello_world
 %22, %7B%0A   
@@ -256,27 +256,16 @@
 rwise(%22/
-hello_world
 %22);%0A  %7D)

Rename /hello_world route to /