This scheme provides for an orderly execution of hooks as the priorities
are controlled from one single place. Enumeration is defined in such a
way that new items can be added easily.
All the event hooks are changed to get the priorities from this
enumeration.
- Add a new variable "name" in WpEventHook and use it to log all the
hooks(by name) picked up in _push_event(). This gives a clear picture
if hook is registered for a given event.
- Form a name for an event and a chain of events for an event run, log
both of them. This gives a clear picture of the events executed and
order in which they are dispatched.
- Similarly build hooks chain and print it in _source_dispatch(), this
gives a clear picture of the hooks picked and the order in which they
are dispatched.
- Log only the dispatchable(with hooks) events, this de-clutters
the log messages.
