Request: Better error handling/communication when tasks are defined on Collections

[griffinmilsap]

Collections cannot have tasks, but if you add tasks/publishers/subscribers to a collection, they'll just silently not run. This needs to be addressed; I just spend like 20 minutes debugging why my subscriber wasn't running, and it was because I accidentially made my Unit inherit from Collection instead of Unit... ugh

[griffinmilsap]

Additionally, this resulted in me creating STATE for the "Collection" which was never initialized (obviously) and resulted in confusing behavior that was unhelpful to tracking down the root issue. We should also issue errors when a subclass of STATE is provided to a Collection.