title: How can I remove all nodes from a scenekit scene?
body: <p>Hi I am trying to remove all nodes from my Scenekit scene but I cannot for the life of me figure out a way. </p>
  
  <p>It seems logical to me that there must be a function for doing this automatically but I cannot find it. </p>
  
  <p>In context, I am trying to remove all nodes so I can reset my scene, which will happen reasonably often. Perhaps there is another way of doing this and I would be fine with that, I'm not stuck with having to remove all nodes.</p>
  
  <p>Thanks!</p>