title: Regular expression for youtube links
body: <p>Does someone have a regular expression that gets a link to a Youtube video (not embedded object) from (almost) all the possible ways of linking to Youtube?</p>
  
  <p>I think this is a pretty common problem and I'm sure there are a lot of ways to link that.</p>
  
  <p>A starting point would be:</p>
  
  <ul>
  <li><a href="http://www.youtube.com/watch?v=iwGFalTRHDA" rel="noreferrer">http://www.youtube.com/watch?v=iwGFalTRHDA</a></li>
  <li><a href="http://www.youtube.com/watch?v=iwGFalTRHDA&amp;feature=related" rel="noreferrer">http://www.youtube.com/watch?v=iwGFalTRHDA&amp;feature=related</a></li>
  <li><a href="http://youtu.be/iwGFalTRHDA" rel="noreferrer">http://youtu.be/iwGFalTRHDA</a></li>
  <li><a href="http://youtu.be/n17B_uFF4cA" rel="noreferrer">http://youtu.be/n17B_uFF4cA</a></li>
  <li><a href="http://www.youtube.com/embed/watch?feature=player_embedded&amp;v=r5nB9u4jjy4" rel="noreferrer">http://www.youtube.com/embed/watch?feature=player_embedded&amp;v=r5nB9u4jjy4</a></li>
  <li><a href="http://www.youtube.com/watch?v=t-ZRX8984sc" rel="noreferrer">http://www.youtube.com/watch?v=t-ZRX8984sc</a></li>
  <li><a href="http://youtu.be/t-ZRX8984sc" rel="noreferrer">http://youtu.be/t-ZRX8984sc</a></li>
  <li>... please add more possible links and/or regular expressions to detect them.</li>
  </ul>