title: angular-ui-select2 query function not defined when used within another directive
body: <p>I'm trying to use the angular-ui-select2 module within another directive but I receive the following error:</p>
  
  <blockquote>
    <p>query function not defined for Select2 undefined</p>
  </blockquote>
  
  <p>When I place the following code in a page of it's own, it works fine:</p>
  
  <pre><code>&lt;input ng-model="select2" data-ui-select2="select2Options" type="hidden" /&gt;
  </code></pre>