title: Jquery scrollto with offset
body: <p>I have this code: <a href="http://codepen.io/anon/pen/pcmdo" rel="nofollow">http://codepen.io/anon/pen/pcmdo</a></p>
  
  <p>However, at the moment when it does the <code>scrollto</code> using the text links in the black menu it scrolls so that the black bar is inside the section. I want to have it so the black bar is on top of the section. just enough to trigger that section as active.</p>
  
  <p>Can anyone show me how to do that. I think it would be something like this (but this is more like sudo code):</p>
  
  <pre><code>scrollTop: $('#'+sectionId).offset().top-nav.height
  </code></pre>