Share on facebook. Add Open Graph meta.

Signed-off-by: Emilien Kenler <hello@emilienkenler.com>
Merge branch 'master' into HEAD
Add support for event  and 'mot du bde' into weekmail - see #68

Signed-off-by: Emilien Kenler <hello@emilienkenler.com>
Merge pull request #77 from MiLk/weekmail

Weekmail
Merge pull request #56 from MiLk/fb-sharer

Fb sharer