Remove RolapCubeMember, RolapMemberInCube, NoCacheRolapCubeHierarchyMemberReader, CacheRolapCubeHierarchyMemberReader, MemberNoCacheHelper. Now, members can only belong to a RolapCubeLevel, not a RolapLevel. Remove a lot of downcasts to RolapMember, RolapCubeLevel and RolapCubeHierarchy, and other cleanup.