Make images display properly

[KingSupernova31]

The editor preview often won't load all of the card images. I suspect this is because of Scryfall rate-limiting blocking some of the requests.

[KingSupernova31]

Oh, we should also have the API return an image url for each card, rather than the client needing to figure that out itself. (Should this url flip flipped flip cards like the RG website does, or leave them unflipped? Not sure.)