Ls/cleanse

Makes call to API to get friends list (limit=1000), and returns an array of VENUser objects. Cleanses JSON response right when it receives the JSON. Can only cleanse if it gets a dictionary, not an array, but can cleanse the array if it's within the dictionary.
Yeah, I see your point. We've already gone on this route with `NSDictionary+VENCore` though, so I think this is fine.