title: Add ancestor selector in current SASS nesting
body: <p>I would like to use Modernizr classes but I can't see how to do it properly with SASS in a current nesting selectors.</p>
  
  <p>How to optimize:</p>
  
  <pre><code>.page-home
      .content
          .rows
              .row
                  background: blue
  
          .images
              width: auto
  
  html.no-touch
      .page-home
          .content
              .rows
                  .row
                      &amp;:hover
                          background: red
  
  html.touch
      .page-home
          .content
              .images
                  max-width: 50px
  </code></pre>
  
  <p>To render something like :</p>
  
  
  
  <pre><code>.page-home .content .rows .row {
      background: blue;
  }
  html.no-touch .page-home .content .rows .row:hover {
      background: blue;
  }
  .page-home .content .images {
      width: auto;
  }
  html.touch .page-home .content .images {
      max-width: 50px;
  }           
  </code></pre>