NO_COLOR support

[kucharskim]

I see many projects using this library, and I don't see simple way to disable colored output for those apps (without code modification). In production environments I like to grep easily logs and colors are making it super difficult.

More info about NO_COLOR environment variable at https://no-color.org/

[AndreasBackx]

If NO_COLOR support is added, might be additionally good to add support for CLICOLOR_FORCE which allows you to always enable it. See http://bixense.com/clicolors/.

[docwhat]

The good thing about standards is that there are so many to choose from.
  - Andrew Tanenbaum

[Timmmm]

The guy who created NO_COLOR was told about the existing and superior CLICOLOR as soon as he announced it. Unfortunately he didn't do the right thing and defer to that standard, so now we have this annoying situation where the worse standard (NO_COLOR) has better marketing.

It looks like bixense has incorporated NO_COLOR into their page but predictably there's no mention of CLICOLOR on no-color.org.