[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/Spell.h

@@ -111,7 +111,7 @@ class SpellCastTargets
             //m_srcY = target.m_srcY;
             //m_srcZ = target.m_srcZ;
 
-            m_mapId = 0;
+            m_mapId = -1;
             m_destX = target.m_destX;
             m_destY = target.m_destY;
             m_destZ = target.m_destZ;
@@ -127,7 +127,7 @@ class SpellCastTargets
         uint64 getUnitTargetGUID() const { return m_unitTargetGUID; }
         Unit *getUnitTarget() const { return m_unitTarget; }
         void setUnitTarget(Unit *target);
-        void setDestination(float x, float y, float z, bool send = true, uint32 mapId = 0);
+        void setDestination(float x, float y, float z, bool send = true, int32 mapId = -1);
         void setDestination(Unit *target, bool send = true);
 
         uint64 getGOTargetGUID() const { return m_GOTargetGUID; }
@@ -155,7 +155,7 @@ class SpellCastTargets
         void Update(Unit* caster);
 
         float m_srcX, m_srcY, m_srcZ;
-        uint32 m_mapId;
+        int32 m_mapId;
         float m_destX, m_destY, m_destZ;
         bool m_hasDest;
         std::string m_strTarget;