message: Update writelooks.py for 1.38.3
  This changelist updates Python script 'writelooks.py' for the 1.38.3 API.  Moving forward, we should consider more modern replacements for the Materials/Examples/Syntax folder and its associated Python scripts, but for now we're preserving them and updating this script to the latest API.
diff: @@ -78,12 +78,8 @@ def main():
  # PropertySet
  #
  propset = doc.addPropertySet("standard")
  - p = propset.addProperty("displacementbound_sphere")
  - p.setTarget("rmanris")
  - p.setValue(0.05)
  - p = propset.addProperty("trace_maxdiffusedepth")
  - p.setTarget("rmanris")
  - p.setValue(3.0)
  + p = propset.setPropertyValue("displacementbound_sphere", 0.05)
  + p = propset.setPropertyValue("trace_maxdiffusedepth", 3.0)
  #
  # Looks
  