code: function consoleErrorLogger(console, yargs, exit, err) {
  	const usage = (!err || err.isUsageError);
  	if (usage) {
  		yargs.showHelp();
  	}
  
  	if (err) {
  		console.log(chalk.red(err.message || stringify(err)));
  	}
  	if (!usage && (err.stack && ((global.verboseLevel || 0)>1))) {
  		console.log(VError.fullStack(err));
  	}
  	// todo - try to find a more controllable way to singal an error - this isn't easily testable.
  	if (exit) {
  		process.exit(1);
  	}
  }
docs: Logs an error to the console given and optionally calls yargs.showHelp() if the
  error is a usage error.
  @param {object} console   The console to log to.
  @param {Yargs} yargs     the yargs instance
  @param {boolean} exit     if true, process.exit() is called.
  @param {object} err      The error to log. If it has a `message` property, that is logged, otherwise
  the error is converted to a string by calling `stringify(err)`.