Skip TTY checks

[aymanbagabas]

Add WithUnsafe options to skip checking for TTY and running IoCtl commands.
This is useful for mocking console output and querying the terminal over SSH.

Fixes: #105 & #108

[heaths]

This works, but seems like sledgehammer to drive a thumbtack. Something like #108 is specific to the original issue in #105. This seems to be intended to just disable everything and isn't intuitive. How would one make the leap from "unsafe" to "tty" support?

[muesli]

I think we want both options, actually. I'm curious, what's your use-case for #108?

[heaths]

It's for tests. I've written a console module I use in various projects and much of it - or its direct dependencies - are based on termenv. The main purpose of that module is being able to test different output for CLIs, mainly for regression tests. I'd like to replace much of what I have rewritten myself with termenv (since it's already a common dependency), but being able to simulate TTY is critical to making that happen.