Fixed #111 -- allow the actor defined within URL configuration to be a Group.

[frasern]

[garemoko]

Thanks for creating this. I'm sure @brianjmiller will want to review this, but just one quick comment from me: I'm personally not keen on the approach of trying to create an agent from the json and then trying group if that fails. I'd prefer to decode the object and get the objectType then try the appropriate one.

[brianjmiller]

+1 to what @garemoko said.