GetLevelByPosition

// A creature can have up to three classes.  This function determines the
// creature's class level based on nClass Position.
// - nClassPosition: 1, 2 or 3
// - oCreature
// * Returns 0 if oCreature does not have a class in nClassPosition
//   (i.e. a single-class creature will only have a value in nClassLocation=1)
//   or if oCreature is not a valid creature.
int GetLevelByPosition(int nClassPosition, object oCreature=OBJECT_SELF);