NO_COLOR requires a non-empty string

[pellared]

Fixes #172

1. Change the handling of NO_COLOR so that the empty string value as equivalent to being unset
2. Some opportunistic fixes

[fatih]

I would like to merge it, but it looks like a breaking change. NOCOLOR="" ./foo is working currently, but with your change we would break this contract. But then, I think the reasoning you provide at #172 make sense.

[pellared]

I would like to merge it, but it looks like a breaking change. NOCOLOR="" ./foo is working currently, but with your change we would break this contract. But then, I think the reasoning you provide at #172 make sense.

It can be seen as a breaking change but for me it is a bugfix for the contract. Especially that https://no-color.org/ is mentioned in the README.md 😉 For sure the change should be clearly (and probably loudly) mentioned in the GitHub release notes. It would be even good to note that setting NOCOLOR="" will have different behavior.

PS. There is no rush for me to merge it. You can consider asking some users for opinion.

[fatih]

You're right. Let's merge it. I'll cut a release in the following weeks.