title: Timespan-Regex with Days-Portion
body: <p>I've just tried several hundreds (if not thousands...) of RegEx's available to get what I want... But none of them worked.</p>
  
  <p>I'm simply looking for a Regular expression, that represents a TimeSpan <code>days.hours:minutes:seconds</code>:
  7.00:00:00 would represent "7 Days"</p>
  
  <p>This one sadly doesn't work:</p>
  
  <p><code>(\d\d).(\d\d):(([0-6][0])|([0-5][0-9])):(([0-6][0])|([0-5][1-9]))</code></p>