Kotlin - First use - Factorial

Everyone proggramer has favorite first program, me too -> factorial in two version:
https://github.com/mikoxp/kotlin_learn/commit/8b8909f30775af4d67db58bddd49a6057e6ab3b2

I think that kotlin is more similar  to java, but the idea of parameters more free.
I'm not complaining. Always something new.