title: Pass object as query string parameter
body: <p>I'd like to pass a search query string to a state.
  The URL should look like this:</p>
  
  <pre><code>/goods?filters[paramA]=1&amp;filters[paramB]=2
  </code></pre>
  
  <p>My state setup is the following:</p>
  
  <pre><code>.state('goods', {
              url:        '/goods?filters',
              …
          })
  </code></pre>
  
  <p>My link template looks like this:</p>
  
  <pre><code>&lt;a ui-sref="goods({ filters: { paramA: 1, paramB: 2}})"&gt;Menu item label&lt;/a&gt;
  </code></pre>
  
  <p>However, ui-router does not encode it properly and I get:</p>
  
  <pre><code>/goods?filters=[object Object]
  </code></pre>
  
  <p>How do I do it properly?</p>