title: how to split a column based on gender
body: <p>Can we split a column using tidyr? Trying to avoid having to use a function.</p>
  
  <p>From this</p>
  
  <pre><code>var1
  Men.2001
  Men.2002
  Women.2001
  Women.2002
  </code></pre>
  
  <p>To this</p>
  
  <pre><code>Gender   Year
  Men      2001 
  Men      2002
  Women    2001
  Women    2002
  </code></pre>