Added translation into French

Hi everyone,
I just finished to update to the last version the translation into French of the lesscss.org repo. I thought it would be great if you guys can include the link in the lesscss.org website.
You can checkout the translated version here: [luckymarmot.com/lesscss](http://luckymarmot.com/lesscss)
The source of that translated version is on this repo: https://github.com/LuckyMarmot/lesscss.org – branch `french`
Thanks!