Also send pointer to AI constructors ans mark constructors as explicit.
This changes allow move now some generic often used AI code to CreatureAI helper functions.
Added checking global cooldown for pet spell casting triggered by master.
Optimized PetAI::UpdateAI:
- Removed obsolete victim_guid as combat check.
- Stop pet combat when pet die in JustDied(Unit*) method.
- Optimized autospells selection and casting.
Signed-off-by: ApoC <apoc@nymfe.net>