title: Regex to parse youtube yid
body: <p>Example URLs</p>
  
  <pre><code>http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo
  http://www.youtube.com/watch?v=cKZDdG9FTKY&amp;feature=channel
  http://www.youtube.com/watch?v=yZ-K7nCVnBI&amp;playnext_from=TL&amp;videos=osPknwzXEas&amp;feature=sub
  http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I
  </code></pre>
  
  <p>Any regex that will pull the correct YID from all 4 of these use cases? The first case is especially odd.</p>
  
  <p>Thank you.</p>