Add circumflex capitals A and O (Â, Ô)

[joallard]

Typing letters "Â", "Ô" is currently not possible with the layout. (Hell, I just had to paste them from the Unicode sheet)

It is thus very inconvenient to type "Âge" and "Ôter".

Thanks for making this layout and making it open source! Cheers!

P.S. J'ai aussi pris la liberté d'ajouter des instructions pour l'installation, pour le côté pratique.