Add tests

Thanks to caching it is quite easy to create tests. You just have to run kaldi-data-generator with the parameters you want and the requests will be saved in /tmp/kaldi_data_generator_{user_name}/cache/. You can then copy them under tests/data/

To rename the files for easier usage you can move them up and rename to {page_id}.json:

# dangerous commands commented out
for x in *; do
  echo $x
  #mv $x/*.json ${x}.json
  #rmdir $x
done