Add flag to force Node colors
So that process that runs in Electron renderer process can log to the terminal if it runs in a headless mode, but to the browser console if it runs with the browser window.
Use case: run browser tests in electron-mocha renderer with or without browser window and still have colors in both cases.
This change also FIXES MASTER. It changes default browser output from console.debug to console.log because the former seems to require a non-default log level to actually output things.
https://developer.mozilla.org/en-US/docs/Web/API/Console :

Coverage decreased (-0.9%) to 86.792% when pulling 6404365c524d7ee8492fb0a9e1bbc584086d288d on artemave:master into 5c7c61dc0df0db4eb5de25707d8cd1b9be1add4f on visionmedia:master.