[svn] Add function GameObject::CastSpell. Used for hunter's trap and so.

Use original caster instead caster to check spell hit result.
Let spell triggers have the same faction as the summoner.
Fix the bug that trigger creatures attack enemy. (no need use civilian extra flag in the future, 128 is enough)
Fix shadow step.

--HG--
branch : trunk

src/game/GameObject.h

@@ -572,6 +572,8 @@ class TRINITY_DLL_SPEC GameObject : public WorldObject
         GameObject* LookupFishingHoleAround(float range);
 
         GridReference<GameObject> &GetGridRef() { return m_gridRef; }
+
+        void CastSpell(Unit *target, uint32 spell);
     protected:
         uint32      m_charges;                              // Spell charges for GAMEOBJECT_TYPE_SPELLCASTER (22)
         uint32      m_spellId;