message: fix missing ospWait() in ospRenderFrameBlocking()
diff: @@ -171,6 +171,7 @@ float ospRenderFrameBlocking(OSPFrameBuffer fb,
  OSPWorld world)
  {
  OSPFuture f = ospRenderFrame(fb, renderer, camera, world);
  + ospWait(f, OSP_TASK_FINISHED);
  ospRelease(f);
  return ospGetVariance(fb);
  }
  