title: Get current index of select on selectize api dropdown
body: <p>I've been using the Selectize API and struggling on determining how to get the index/position of the currently selected item.</p>
  
  <p>I've looked at the API and found the getValue() to get the value of the selected item but I need the index. I also investigated the .selectize option itself but can't seem to find any attributes that store it?</p>