Serbian cyrillic translation

We need to mention somewhere how to maintain serbian translation.

We should maintain cyrillic translation and just build latin with [Fåtölj](https://github.com/umpirsky/Fatolj).
Because if we do other way around placeholders like `%count%` can be transliterated to %цоунт% :)

Where is the right place to mention this @pjedrzejewski?