binary: Accepts piped input from stdin. Fixes #448

Issues
---
- [x] no output when the file being `cat`'d is blank
- [x] we should document the usage of this feature in the readme

Fixes #448 
This should probably be `if (process.argv.length === 2)`.

This triggers the piped stdin processing if `jscs` is invoked via `node jscs`, as in, the `jscs` command is invoked without arguments.