title: How to use Durandal's createChildRouter
body: <p>I have struggled all day unable to figure out how to properly create a child router using Durandal in my hot towel-based (MVC4 SPA) project. This is what I have at the moment:</p>
  
  <h2>shell.js</h2>
  
  <pre><code>var routes = [
      { route: '', moduleId: 'home', title: 'Home', nav: 1 },
      { route: 'inventory/index', moduleId: 'inventory/inventory', title: 'Inventory', nav: 2 }];
  return router.makeRelative({ moduleId: 'viewmodels' }) // router will look here for viewmodels by convention
      .map(routes)            // Map the routes
      .buildNavigationModel() // Finds all nav routes and readies them
      .activate();            // Activate the router
  </code></pre>
  
  <h2>inventory.js</h2>
  
  <pre><code>define(['services/logger', 'plugins/router'], function (logger, router) {
      var title = 'Details';
      var childRouter = router.createChildRouter()
        .makeRelative({
           moduleId: 'viewmodels/inventory',
           fromParent: true
        }).map([
              { route: '', moduleId: 'inventory', title: 'Inventory', nav: 3 },
              { route: 'items', moduleId: 'items', title: 'Items', nav: 4 }])
          .buildNavigationModel();
      var vm = {
         router: childRouter,
         activate: activate,
         title: title
      };
  
      return vm;
  
      //#region Internal Methods
      function activate() {
         logger.log(title + ' View Activated', null, title, true);
      }
      //#endregion
  });
  </code></pre>
  
  <p>The problems I currently have:</p>
  
  <ol>
  <li>Inventory view is activated twice when I click on it</li>
  <li>No further navigation options become visible, although some empty 3D rounded rectangle appears in the upper right... I'm not sure if that's a progress bar that failed to go away or some failed navigation element.</li>
  </ol>
  
  <p>My project files are organized like this:</p>
  
  <p><img src="https://i.stack.imgur.com/ERTt7.png" alt="Project file tree structure"></p>