[crossfire] Old event system cleaning

[Nicolas Weeger (Laposte)]

Hello.

Unless someone objects really much, I'd like to trash the old plugin/event 
system.

It is based on the "event_trigger" and such lines in the archetype definition, 
and includes a few functions/fields (object->event for instance).

With the archetype-based event system, it is obsolete.


Currently, only artifacts of occidental mages (ring and weapon) still use it. 
Not even sure that works :)
We'll need a way to add inventory through the artifacts, actually.

I checked the maps, and none uses that system anywhere.


Nicolas