title: Dynamically generated route-href throws error
body: <p>I'm trying to dynamically generate a <code>route-href</code> in a list of items. I basically have this:</p>
  
  <pre><code>this.items = [
      {
          name: 'Foo',
          route: 'item',
          routeParams: {
              id: 1
          }
      },
      {
          name: 'Bar',
          route: 'item',
          routeParams: {
              id: 2
          }
      }
  ];
  </code></pre>
  
  <p>And in my view:</p>
  
  <pre><code>&lt;ul&gt;
      &lt;li repeat.for="item of items"&gt;
          &lt;a route-href="route: ${item.route}; params.bind: ${item.routeParams}"&gt;
              ${item.name}
          &lt;/a&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>But Aurelia tells me:</p>
  
  <pre><code>aurelia-logging-console.js:54 ERROR [route-href] Error: A route with name 'undefined' could not be found. Check that `name: 'undefined'` was specified in the route's config
  </code></pre>
  
  <p>If I print the <code>${item.route}</code> and <code>${item.routeParams}</code> they do contain the correct values:</p>
  
  <pre><code>&lt;ul&gt;
      &lt;li repeat.for="item of items"&gt;
          &lt;a route-href="route: ${item.route}; params.bind: ${item.routeParams}"&gt;
              ${item.name} ${item.route} ${item.routeParams}
          &lt;/a&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>Why? :/</p>