IResultPoint Interface

To mimic "garbage collection" (or ARC) with old-gen compilers we have to use interfaces. IResultPoint is the interface that maps TResultPoint which is now implemented as a TInterfacedObject descendant which supports automatic deallocation based on reference counting of interface variables. See ZXing.ResultPointImplementation to see the actual implementation of this interface. since we are using automatic reference counting, we don't need the Clone method any more.