No hard-coded event images

[appakz]

When creating an event I'd like to be able to define images to show on the main page carousel dynamically.

Simplest way to implement this would be to allow for users to enter one or more image URLs (to a hosted site like flickr, dropbox, Amazon storage, whatever) and then just have the carousel render tags for each one. That way we won't have to worry about letting people upload images to the event site itself.