Updating infrastructure

[bsipocz]

This may be a red herring, but I would like to figure out whether the dependency on the helpers is coming into play to radio-astro-tools/spectral-cube#538 from this package or somewhere else.

Gradual commits with updates to different parts of the infrastructure.

[coveralls]

Coverage remained the same at 54.495% when pulling f517991 on bsipocz:update_infrastructure into f738bf6 on radio-astro-tools:master.

[coveralls]

Coverage increased (+0.7%) to 55.187% when pulling 44ca16b on bsipocz:update_infrastructure into f738bf6 on radio-astro-tools:master.

[bsipocz]

@keflavich - This is passing now, thus mergeable.