title: jQuery-ui Autocomplete show all values if no matching value found
body: <p>Is it possible with jQuery Auto-complete, to make it so that if there are 'source:' values available, but they don't match what you are typing, then just show all the sources at once?</p>
  
  <p>IE, given the following code, if I type in "pineapple", how do you show all the programming languages instead of none of them?</p>
  
  <pre><code>&lt;script&gt;
  $(function() {
      var availableTags = [
          "JavaScript",
          "Perl",
          "PHP",
          "Python",
          "Ruby"
      ];
      $( "#tags" ).autocomplete({
          source: availableTags
      });
  });
  &lt;/script&gt;
  &lt;input type="text" id="tags" /&gt;
  </code></pre>