title: How many seconds from midnight until specific Datetime
body: <p>Is there a nice simple shorthand way of finding out how many seconds past midnight a certain datetime is? Not how many seconds it is away from now, the seconds past in that day</p>
  
  <p>eg:</p>
  
  <ul>
  <li><code>2015-04-10 00:00:00</code> should returns <code>0</code></li>
  <li><code>2015-04-12 09:20:00</code> should returns <code>33600</code></li>
  <li><code>2015-04-14 15:20:00</code> should returns <code>55200</code></li>
  </ul>
  
  <p>Is there a nice short method of doing this?</p>