title: Batch not-equal (inequality) operator
body: <p>According to <a href="http://tldp.org/LDP/abs/html/dosbatch.html" rel="noreferrer">this</a>, <code>!==!</code> is the not-equal string operator.
  Trying it, I get:</p>
  
  <pre><code>C:\&gt; if "asdf" !==! "fdas" echo asdf
  !==! was unexpected at this time.
  </code></pre>
  
  <p>What am I doing wrong?</p>