Fixed some punctuation and added the missing translations for French

Here are the missing translations. There were a few liberties taken with the original translation that I have not "fixed". "Third party account" was translated as "social network account" in a few places and that it not correct but I didn't change it. I also homogenised the punctuation and corrected a couple that were wrong (there is always a space before a ?, etc.). I'm guessing it's here and not in transifex that I have to do this!