Implemented a .bif serializer, to bayesian/serializer/bif.hpp
Implemented a .bif serializer, to bayesian/serializer/bif.hpp

Signed-off-by: Godai Azuma <0f0eab2b3ee7eed768c2dfe49c6ee6c6ec6e6a5d@gmail.com>

godai0519/BayesianNetwork