Testing basic functionality of WI.EventListenerSet.

Registering listeners.
Installing listeners.
Dispatching events.
Invoked callback for foo event.
Invoked callback for bar event.
Invoked callback for baz event.
Uninstalling and disconnecting listeners.
Registering listeners.
Dispatching events.
Invoked callback for foo event.
Invoked callback for bar event.
Invoked callback for baz event.
Uninstalling listeners.
Installing listeners.
Dispatching events.
Invoked callback for foo event.
Invoked callback for bar event.
Invoked callback for baz event.
Unregistering everything.
Dispatching events.
Uninstalling and disconnecting listeners.
Dispatching events.