I think we should allow warnings (i.e. remove ``--errorsonly``) and see if it's too noisy or not. Here's an example of a warning:

````
Warning: mismatched: missing variables: %(author)s
msgid "Other add-ons by %(author)s"
msgid_plural "Other add-ons by these authors"
msgstr[1] "Ander byvoegings deur hierdie outeurs"
```
This is a problem because it will actually raise an exception in Python: 'unmatched format string' or something