fix persistently published points
This commit (4247bfd0) introduced a bug for the TOF (and potentially elsewhere?) point cloud data - since the message data was pass-by-ref and points are gated with tof_cutoff
, if a pixel with a high confidence suddenly has a low confidence, the last high confidence z value will be kept, making it seem like objects are still in the fov.
probably need to double check the point cloud interface (and others) - but i did not.