Removing the testing directory and add it to .gitignore

* the testing directory was always just a collection of some
  some scripts that to me have no real meaning
* I mostly use it to try something out e.g. programs posted in
  issues
* By ignoring it we can use it for testing scripts without having
  to worry about accidentally committing something or having many
  untracked files around

I'd wanna have like at least 2 thumbs up and no one against this change before I merge it, because maybe I just misunderstood the testing directory :-)