title: jsTree disable moving some nodes
body: <p>I have a single jsTree and I want some of its nodes to be moveable. The root node and its immediate children cannot be moved.</p>
  
  <p>I am using crrm and it works as expected but it still allows me to drag all nodes, even those nodes (immediately below root) that cannot be dropped anywhere. I don't want them to be draggable at all i.e. user should not be able to pick them up at all.</p>