rktcc

It was raised to my attention that it seems the Japanese character sets are not present in the [scc codes file](https://github.com/sandflow/ttconv/tree/master/src/main/python/ttconv/scc/codes), thus I imagine this might be a difficult task...

> @rktcc Can you provide a link to the forum discussion thread? I could not find any specification for carrying arbitrary unicode characters in SCC. Hi, I am sorry for...