title: Regex: find email address when not wrapped in HTML <a> tag
body: <p>Given a text with email addresses I would like to match all the ones that are not wrapped inside an "a" tag. And I can only do it with a regex.</p>
  
  <p>THIS MATCH:</p>
  
  <pre><code>something@something.else
  </code></pre>
  
  <p>THIS DOES NOT MATCH:</p>
  
  <pre><code>&lt;a href="mailto:someone@example.com?Subject=Hello%20again" target="_top"&gt;Send Mail&lt;/a&gt;
  </code></pre>
  
  <p>Anyone? Thanks.</p>