message: QuadMesh geometry.  Add fallback param name "normal".
  Added a fallback getParam name of "normal" if "vertex.normal" isn't
  found.  Now matches TriMesh behavior.
diff: @@ -58,7 +58,7 @@ namespace ospray {
  RTCScene embreeSceneHandle = model->embreeSceneHandle;
  vertexData = getParamData("vertex");
  - normalData = getParamData("vertex.normal");
  + normalData = getParamData("vertex.normal",getParamData("normal"));
  colorData = getParamData("vertex.color");
  texcoordData = getParamData("vertex.texcoord");
  indexData = getParamData("index");
  