Merge pull request #330 from 9seconds/telemt

Mention telemt project in README

README.md

 * [Official](https://github.com/TelegramMessenger/MTProxy)
 * [Python](https://github.com/alexbers/mtprotoproxy)
 * [Erlang](https://github.com/seriyps/mtproto_proxy)
+* [Telemt (Rust)](https://github.com/telemt/telemt)
 
 You can use any of these. They work great and all implementations have
 feature parity now. This includes support of adtag, replay attack