Small fix for when selectbox destroyed

This is a fix for this case:

--  If a selectbox is destroyed but in code you still use this code 
  $('#element').selectBox('options', data)  the select won't get changed with the new options

  Changes made for selectbox to work when disabled
 
   remove code " if (selectBox =  $(this).data('selectBox'))  {"   from method     $.extend($.fn, { Selectbox:  
   inside the case with "options"  (because the code was only working if the selectbox was enabled)
   
   move method  SelectBox.prototype.setOptions inside  $.extend($.fn, {  setOptions
   and set the select variable to   $(this) instead of $(this.selectElement) 
   and for refresing replace code  this.refresh();  with  $(this).selectBox('refresh');
  
 There might be better ways of dealing with this, but this fixed the issue for me. 
 I hope you will find it useful