message: Better demo explanation
diff: </ul>
  <button class="add_image">Add another image</button>
  - <h2>With history enabled</h2>
  + <h2>With history & permalinks</h2>
  <ul class="demo_history">
  <li><a href="images/demo1.jpg" data-imagelightbox="j"><img src="images/thumb1.jpg"></a></li>
  <li><a href="images/demo2.jpg" data-imagelightbox="j"><img src="images/thumb2.jpg"></a></li>
  <pre><code>$('a[data-imagelightbox="hist"]')
  .imageLightbox({history: true});
  </code></pre>
  + <pre>Call with ?imageLightboxIndex=2 added to the url to open the third image
  +(may need to add &imageLightboxSet=j as well because there are multiple examples)</pre>
  - <h2>Deep links</h2>
  + <h2>History with ids</h2>
  <ul class="demo_activity">
  <li><a href="images/demo1.jpg" data-imagelightbox="k" data-ilb2-id="img1"><img src="images/thumb1.jpg"></a></li>
  <li><a href="images/demo2.jpg" data-imagelightbox="k" data-ilb2-id="img2"><img src="images/thumb2.jpg"></a></li>
  <li><a href="images/demo3.jpg" data-imagelightbox="k" data-ilb2-id="img3"><img src="images/thumb3.jpg"></a></li>
  </ul>
  - <pre>Add data-ilb2-id="img2" to images and call with ?imageLightboxIndex=img2 added to the url</pre>
  + <pre><code>$('a[data-imagelightbox="hist"]')
  + .imageLightbox({history: true});
  + </code></pre>
  + <pre>Add data-ilb2-id="img2" and call with ?imageLightboxIndex=img2 added to the url to open that image
  +(may need to add &imageLightboxSet=k as well because there are multiple examples)</pre>
  <h2>Press enter for fullscreen</h2>
  <ul>
  