Remove dummy nodes.

Слиты nikitronn запросил слияние remove_dummies в master

Created by: Durman

Addressed problem description

Instead of dummy node a Dependency error is shown.

image

To add dependency to a node it's enough to add extra class variable.

class SvDelaunay3dMk2Node(SverchCustomTreeNode, bpy.types.Node):
    sv_dependencies = {'scipy'}

Preflight checklist

  • Code changes complete.
  • Code documentation complete.
  • Manual testing done.
  • Ready for merge.