title: selectize.js accumulates options from previous searches
body: <p>I found that selectize accumulates options from previous searches.
  I upload new list of options remotely from my server and the number of selected items not limited. In this case after several searches in dropdown I have a lot of options connected with old queries which I don't need.
  How can I avoid this?
  List of selectize options for initialize</p>
  
  <pre><code> valueField: 'id'
   labelField: 'label_name'
   searchField: 'city_name'
   options: []
   create: false
   openOnFocus: false
  </code></pre>
  
  <p>Thx for any help.</p>