Add Support for French

[mtrythall]

French labels aren't all translated. We need to know:

1. How to translate the system
2. Get proper support for French in place

[nicolaslara]

There is native support for french, but not everything is translated. I'll investigate how to override this.

[nicolaslara]

I experimenting with overriding the language files to improve the translations. This wasn't straightforward and my mean we'll have to choose between leaving translations as they are or forking.

I'll experiment with other ways of overriding the po files and post back.

[nicolaslara]

This turned out to be considerably more complicated than I expected. I'm moving this to post-launch in favour of other priorities.