Update List.h
Update List.h

Conversion to the STL list will be implemented later
alesiong/CUHKSZLib,alesiong/CUHKSZLib,cuhkshenzhen/CUHKSZLib,cuhkshenzhen/CUHKSZLib,Yexiaoxing/CUHKSZLib,cuhkshenzhen/CUHKSZLib,Yexiaoxing/CUHKSZLib,Yexiaoxing/CUHKSZLib,alesiong/CUHKSZLib