title: xls2csv skipping bool values when converting
body: <p>I'm attempting to use catdoc -> xls2csv on an Ubuntu 14.04.1 OS to convert and .xls file to a .csv file. All of the values are converting correctly except in the last column which contain TRUE/FALSE values.</p>
  
  <p>I've attempted to add columns before and after with multiple types of input data and it all is recognized except for the TRUE/FALSE values which are left blank</p>
  
  <p>Example entry in XLS</p>
  
  <blockquote>
    <p><code>Id  Site       Name IsCustomer 
    123 google.com eric TRUE</code></p>
  </blockquote>
  
  <p>Output in CSV</p>
  
  <blockquote>
    <p><code>Id  Site       Name IsCustomer
    123,google.com,eric,,</code></p>
  </blockquote>