JsonArray's should be converted back to a List on the receiving side.

So I noticed that we convert from List to JsonArray when sending, but back on the receiving side we do not. Surely if I send a List over the EventBus I should get a List back ? 

However it should be noted this could possibly break existing code if they do indeed expect a JsonArray on the receiving side. 

This is more in line with how we treat JsonObject -> Map as well.