title: Random value from c# enum variable
body: <p>Is there an easy way for me to select a random bit value from my enum variable?<br>
  For example:</p>
  
  <pre><code>[System.Flags]
  public enum Direction{
      None = 0,
      Up = 1,
      Down = 2, 
      Left = 4, 
      Right = 8,
      All = ~None
  }
  
  public Direction someDir = Direction.Up | Direction.Down;
  </code></pre>
  
  <p>I would want to select a random positive bit value from <code>someDir</code> so that I could only have <code>Direction.Up</code> or <code>Direction.Down</code>?</p>