i18n: make catalog compile work from setup.py
Missing 'domain' default
N_ -> ngettext in tpls to avoid confusion

Also fixed date formatting (localization)
Properly handle lazy strings
Add unit tests for i18n
Fix french translation according to changes
Move with_zodb decorator to indico.core.db.util
Fix typos
Add grouper util (iterates in chunks)
Add skip_missing+doc to grouper; add unittest
Check for _LazyString instead of LazyProxy
Fix default language selector
Sort language selector and uppercase first char
Update signal docstring