Usage: zanata_stats.py -s 2015-08-01 -e 2016-01-31 translation_team.yaml
zanata_stats.py will query translator's contributions in words,
including the translated translations, approved translations
and rejected translations, in a certain period of all projects and all
versions, and then save the data in a csv file.
translation_team.yaml stores all translation team and translators information.
Co-Authored-By: Akihiro Motoki <amotoki@gmail.com>
Change-Id: If7b92cb2e7ccc3e2e59d977976d7c5d726e606dd