[ArmA] Extended Event Handlers by Killswitch & Solus

This addon allows a virtually infinite amount of event handlers to be used
together from different addons. The event handlers are executed for the matching
class and all inheriting classes. The event handler init line also contains the
extended event handler class to look for, so you can have a custom inheritance
for custom units.

Normally event handlers can only be added in configs, and trying to add a new
event handler caused all previous event handlers to be overwritten. This addon
allows that limitation to be overcome. This is mostly useful for having addons
that can add different functionality, for example in OFP addons that had their
own event handlers wouldn't inherit default event handlers, such as a custom
unit with EHs being used with ECP or FFUR wouldn't have the ECP or FFUR effects.