Update the pot file to match current source, and pull
translations from Transifex
The commands used to create this commit were:
tx pull -fa # needs an account and transifex client setup
cd install/po
make update-pot
(update LINGUAS to contain all languages with translations, and no empty ones)
make update-po
Our LINGUAS file and the set of po files have diverged from what's on
Transifex. We should update the LINGUAS file to match the set of
translations on Transifex and add po files currently on Transifex but
not in our git repo to our git repo.