U/jchiang/use stack sims w 2019 42

[jchiang87]

No description provided.

[coveralls]

Coverage increased (+0.08%) to 73.032% when pulling 158ab3c on u/jchiang/use_stack-sims_w_2019_42 into be926d2 on master.

[jchiang87]

Before the iers workaround:
https://travis-ci.org/LSSTDESC/imSim/builds/605136802

and after:
https://travis-ci.org/LSSTDESC/imSim/builds/605166758

Unfortunately, the error from the first (failed) build doesn't actually look the error James saw in his Grid run. I'm hoping that by using a very recent file in the workaround that he won't see the IERSRangeError

[cwwalter]

IERS part looks good. A single line comment before

_disable_iers_download(my_config)

would be probably be useful to the reader to tell them what is going on.

Thanks! It's great to finally have a real solution to this in the code.

[jchiang87]

Thanks! Unless I hear otherwise by 5pm PT today, I'll merge this and will make a patch release.