Add Events: Attack of Opportunity events and Creature: BroadcastAttackOfOpportunity

[summonFox]

Events:

• Adds skippable event NWNX_ON_BROADCAST_ATTACK_OF_OPPORTUNITY_{BEFORE|AFTER} which allows skipping a creature provoking attacks of opportunities from enemies.
• Adds skippable event NWNX_ON_COMBAT_ATTACK_OF_OPPORTUNITY_{BEFORE|AFTER} which allows stopping a creature from performing an attack of opportunity against a target.

Creature:

• Adds BroadcastAttackOfOpportunity()