Update readme and minor changes

[sphinks]

I try to use this tap to get data from bigquery, but have to fix several issues, so doing backmerge PR.

1. Fix readme.
2. Add output of state message to be compatible with any target.
3. Fix lost require lib in setup script.

[daigotanaka]

@sphinks Thanks for improving the code and docs! Looking good.

[daigotanaka]

@sphinks Can you review this (breaking change v0.3.0)
#3
I also wanted to discuss the release on PyPi since you did that with the previous version. Thx!

[sphinks]

@daigotanaka I'm not really good with Python, but I do not notice any issues. Also, I'm not sure I can be mentioned as author yet (just fix couple issues:)), I suppose contributor is much closer to the truth :)

Do you want me to release it on PyPi? Or, I can delete my release on PyPi in case you want to release it by youself.

[daigotanaka]

@sphinks got it about contributor. Can you add me (daigotanaka) as a collaborator at https://pypi.org/manage/project/tap-bigquery/collaboration so I don't have to contact you every time I need to release? Thx!

[sphinks]

@daigotanaka done, you can use it.

[daigotanaka]

Thx @sphinks ! ...also letting you know that I'm changing the repo name to tap-bigquery from tap_bigquery to be consistent with the pypi release name.

[sphinks]

It is make sense!