add French translation

![](https://photos-2.dropbox.com/t/0/AABSo_a-IFpTJftG48HqnfE7xynmUn_ews2RIc_afHpyKg/12/112486086/png/1024x768/3/1384038000/0/2/french_mozstumbler.png/Go4cetxaOALHsZFoOfNuLJZ8Fc7dZU5wfFwdKM0hHaY "Nexus 5 snapshot")