Core/Pets: merged funjoker's new Pet Slot system

* fixed packets and handling for stable master
* fixed Control Pet / Demon handling
* corrected wrong trainer spell for the Control spells
* Added base support for Assist behaivior
* corrected action bar layout
* Hunter Pets will now have the same level as their tamer (patch 4.1 change)
* corrected health stats for pets

src/server/scripts/Commands/cs_npc.cpp

@@ -1452,7 +1452,7 @@ public:
         // caster have pet now
         player->SetMinion(pet, true);
 
-        pet->SavePetToDB(PET_SAVE_AS_CURRENT);
+        pet->SavePetToDB(PET_SAVE_NEW_PET);
         player->PetSpellInitialize();
 
         return true;