Create roll.js

Add event handling for rolling and stop action.
Add default member photo.
Add reference to roll.js
Add rolling and stop button.

Add a list of all the RSVPs for easier implementation. In this way, we
don't need another roundtrip to the server to get the member photo.
Add some style for newly added page elements.
Generate random rsvp on the client side.

Send rsvp list instead of random rsvp to the client side.
fix issue with groups with missing image/logo