- converts .xz files to .gz recursively

- graphdb wants .gz files; so there we go

While I do not intend to use this again it's nice to have all in one
place (i.e. this repo).

- It does work but I don't think this db is very
  production-ready/friendly

- It does show that the dataset works as it is
  distributed. So it should work in other DBs as
  well.

If this destroys your file system I am sorry, but I'd like
to experiment w/ keeping everything in one place.

- /timeline will hopefully contain what I did every week and what I plan for
  the next.

- For keeping track I just use simple text files. Sorry orgmode users!