Added new type-safe cast functions.

This, when properly used, should get rid of most memory corruption issues,
currently, casting types C-style with no checks leads to some abstract crashing.
Functionality is same as with dynamic_cast<>, but with no RTTI check - so when
casting into invalid type you will receive NULL, and most probably crash.
At the same time, i took the liberty to convert most Player* casts to ToPlayer().
Still needs crapload of casts being moved to new facility.

--HG--
branch : trunk

src/game/Creature.h

@@ -663,6 +663,7 @@ class Creature : public Unit, public GridObject<Creature>
         static float _GetDamageMod(int32 Rank);
 
         float m_SightDistance, m_CombatDistance;
+
     protected:
         bool CreateFromProto(uint32 guidlow, uint32 Entry, uint32 vehId, uint32 team, const CreatureData *data = NULL);
         bool InitEntry(uint32 entry, uint32 team=ALLIANCE, const CreatureData* data=NULL);