17. Reweight visibilities

Calculate data weights based on st. dev. within each spw.

No pipeline QA for this task.
vis
['/scratch/VLA-2015/dataset-1/Dataset-1-Qband.ms', '/scratch/VLA-2015/dataset-1/Dataset-1-Kaband.ms', '/scratch/VLA-2015/dataset-1/Dataset-1-Kband.ms']
Start time
2018-11-28 18:36:31.397
End
2018-11-28 18:53:34.010
Duration
0:17:02.614

CASA logs for stage 17