[PATCH 0 of 3] Check format string strings in translations

[Martin Geisler]

Hello,

As discussed on IRC, it is actually possible to make msgfmt check the
format strings for differences between the original and translated
string. This is done by letting xgettext extract the strings instead
of pygettext and invoking msgfmt with a -c flag.

The build_mo command in setup.py will now abort if an error is
detected in the translation.