fails to detect if in piped or standalone mode when run as a child process

[maxlath]

the only solution found to check the process state (piped or run alone) is hacky, relying on process.stdin.isTTY, and fails in child process mode
http://stackoverflow.com/questions/15466383/how-to-detect-if-a-node-js-script-is-running-through-a-shell-pipe/15485424#comment71811390_15485424

• problematic line: lib/parse_arguments.js#L1-L3
• failing test: test/cli.js#L21-L32