title: Find the max distance of any two points in a point cloud?
body: <p>I have a point cloud and I want to find the max distance between any two points in this cloud.</p>
  
  <p>The algorithm came to my mind is to write two "for" loops and compare every distances. But I guess that is not smart enough...</p>
  
  <p>Is there any existing function in PCL to do this? Or any idea of better algorithm?</p>