Korean language added

hello.
First, I know already exist pull request for Korean by itstake, 5 days ago.
actually i don't know about that "Korean pull request" at before complete my translate work. :(
please judge my pull request.

1. My script based on "Official Mobile Telegram Korean version (iOS)".
2. Some Mac OS X scripts are not translate.
3. Test done.

I'm sorry I made things more complicated.
If you don't need, please drop this :)