This PR early returns the on_examine proc for deadchat control if the examiner is not an observer.
So, only ghosts (deadchat) are allowed to see if something is under deadchat control. Humans don't need to know (or shouldn't know) if deadchat is expanding its reach into the physical realm.
Loosely adapted from /vg/. This is an entity component system for adding behaviours to datums when inheritance doesn't quite cut it. By using signals and events instead of direct inheritance, you can inject behaviours without hacky overloads. It requires a different method of thinking, but is not hard to use correctly. If a behaviour can have application across more than one thing. Make it generic, make it a component. Atom/mob/obj event? Give it a signal, and forward it's arguments with a SendSignal() call. Now every component that want's to can also know about this happening.
See this thread for an introduction to the system as a whole.