More on MiniListener event registry.

* Do not pass isCancelled to nodes.
* Query if an event is cancelled is done by a method.
* Allow cancelling of events during processing.
* Adding MiniListener instances splits to two stages represented by
methods by default (create ListenerEntry + add entry to internals).
* Add the base priority type to MiniListernerNode.
* Implement basic parts so they could work [untested].
Contemplate on a monotonic clock provider.