*CreatureGroups fixed and improoved. By TrullyONE

- Multimap support for instances added.
 - Removed redundant group checks.
 - New movement rules (bool group formed/dismissed added).
 - uint32 Creature::GroupID replaced with CreatureGroup pointer.

--HG--
branch : trunk

src/game/MotionMaster.cpp

@@ -525,9 +525,9 @@ void MotionMaster::DelayedDelete(_Ty curr)
 
 bool MotionMaster::GetDestination(float &x, float &y, float &z)
 {
-   if(empty())
+	if(empty() || !Impl[i_top] || isStatic(Impl[i_top]))
        return false;
-
-   return top()->GetDestination(x,y,z);
+	
+	return top()->GetDestination(x,y,z);
 }