Add opengrapgh to SmartCrawl

Hello hello !

Please is it possible to add a feature to add Facebook API to the plugin. The Facebook API ID is pretty necessary to use open graph as FB says :

The 'fb:app_id' property should be explicitly provided so that stories shared to Facebook will be properly attributed to the app.

Also, include tags for Linkedin and Twitter so we'll have a full SEO plugin ! :p

Thank you!