Adding FR translation

Hi,

I greatly appreciate your plugin, that meets recurrent needs i didn't took the time to fulfil until i discovered your work...
So here's a little contribution with the FR translation.

I've read the numerous comments on the community site, and agree to some of them : i think the choice hasn't been clearly made between "merging users" and "transmitting content", each of which implying a different design.
I might submit some changes depending on our usage of the plugin, if you're OK with that, i'll keep in touch so eventual changes could be integrated into your plugin.

Regards,
Florian