[sr] Adding Serbian language support

Hi,

I am thinking of adding support for Serbian language to LT. However, one thing is not clear to me: requirement that language is maintained. How is that measured?

I am a professional software developer that likes to develop software in his spare time as well. However, spare time is not something one can easily plan. There may be time when I won’t commit to LT repository for a week or two, but then I will make it up in a couple of days. So, there may be “spikes” in Serbian language support in LT.

I already forked LT repository for Serbian language here, but I’d prefer having things clear before making a “pull” request.

I consider a language unmaintained if nothing is going on for several months. One or two weeks without a commit are not an issue.