Optionally disable colorized output

[harto]

Would it be possible to always disable colorization of log output?
I'm running into the issue described here: https://groups.google.com/forum/#!topic/magit/oMNrMUvxTTs

It seems like Overcommit::Logger#color could additionally read some configuration option (environment variable?) and decide whether to include the ANSI escape sequences or not.

Would you accept a PR along those lines?

[sds]

Hey @harto, thanks for opening an issue.

Would happily accept a pull request adding support for enabling/disabling of color via an environment variable. I would think OVERCOMMIT_COLOR should suffice, here. Thanks!