tv:isdbt as TV source
Hello, I live in Japan and the tvsource type for terrestrial broadcast is isdbt. None of the other (dvbt, dvbc, dvbs) types work here. 
Would it be possible to add those (isdbt, isdbc, isdbs) to the dropdown in the UI configuration screen? of course I can always edit the config by hand (which I did) and it works just fine. But as there are a few countries using it, I think it might be worth adding?
https://en.wikipedia.org/wiki/ISDB

cheers, thanks for the great work!