Add support for semicolon separated value

[nootmuskaat]

For lack of a better name, I've called it ssv for semicolon separated values.

At this point the csv.lua, tsv.lua, and now ssv.lua files are nearly identical and one could refactor instead. Let me know if you'd prefer that approach.

[nootmuskaat]

This should resolved issue #3 , I forgot to mention