Added facebook open graph tags

I added some facebook open graph tags and a pokemon screenshot so fb posts like this:

https://www.dropbox.com/s/w2bbq98ijv7ec0f/Screenshot%202014-03-17%2000.30.12.png

will look more like this:

https://www.dropbox.com/s/e8pka2mb8zpn8c3/Screenshot%202014-03-17%2000.33.30.png