title: Regex lookaround with special characters is invalid?
body: <p>I am trying this regex</p>
  
  <pre><code>(?&lt;!(John|Joe)) (Taylor)
  </code></pre>
  
  <p>On this text
  <code>John James Taylor</code></p>
  
  <p>but I am getting "invalid pattern in lookbehind" here <a href="http://www.rubular.com/r/TjD2d4oG5z" rel="nofollow">http://www.rubular.com/r/TjD2d4oG5z</a></p>
  
  <p>I am trying to match "Taylor" that does not have John or Joe before it.</p>
  
  <p>Any tips please?</p>