AI Condition target entity dependency

This is kind of important for making advanced AI.

The "attack entity of type" goal or any related goals must have inside its condition a dependency on the entity the AI is targeting.

Here is a use case for this feature:

Say there is a player bounty system where the more you kill and steal the higher the bounty that is stored in the player global variable. The AI goal condition needs the said bounty to determine if the mob wants to fight the player or not. e.g. if player_bounty > 1000 then return true; 

So any goals' conditions that require mob interaction with another entity (like "attack entity of type") need a dependency that stores the other target entity. This small feature can allow you to make better mods just a bit easier.