Update Vocabulary Data Source

[tentoumushii]

Use the following data source: https://github.com/stephenmk/yomitan-jlpt-vocab/
Convert the data to .json format prior to using, properly credit the source.

[hanserlodev]

One question, there are missing elements in some columns of some files, do we just omit them or include them anyway? Also, everything should be in vocab/jlpt in their respective folders and the correct files, right?

[tentoumushii]

I think we just leave them blank like that. We include the JSON key-value entry, but leave the value as an empty JavaScript string - I'm working on it right now, and I'm going to create a fork of the repo I linked above but with the JSON-format data soon