Fix compilation with latest VapoutSynth headers
Fix compilation with latest VapoutSynth headers

propSetNode how expects a non-const pointer to a VSNodeRef, as
of r308.

Signed-off-by: Derek Buitenhuis <aff7d637ede26ea82e5226e01b697996cc52e526@gmail.com>

dwbuiten/d2vsource,dwbuiten/d2vsource