Cleanup and reorganization of Unit and SpellEntry headers. (#312)

* Move some unit and spell defines to dedicated header.

* Reorder functions in unit header.

* Clean up until spell category.

* Finish cleaning up spell functions.

* Cleanup combat system methods.

* Done cleaning up unit header.

* Reduce not needed includes.

src/game/ScriptMgr.cpp

@@ -2605,7 +2605,7 @@ WorldObject* GetTargetByType(WorldObject* pSource, WorldObject* pTarget, uint8 T
             return pTarget;
         case TARGET_T_HOSTILE:
             if (Unit* pUnitSource = ToUnit(pSource))
-                return pUnitSource->getVictim();
+                return pUnitSource->GetVictim();
             break;
         case TARGET_T_HOSTILE_SECOND_AGGRO:
             if (Creature* pCreatureSource = ToCreature(pSource))