function getConfigFromCommandLine(argv) {
	const options = {};
	forEach(argv, (value, key) => {
		if (key.startsWith('config:')) {
			options[key.replace(/^config:/, '')] = value;
		}
	});
	return options;
}
Get config options from command line, passed as --config:foo bar.

@param {Object} argv
@return {Object}