changed TabularCPD class to inherit Factor; added reduce, marginalize, normalize methods
changed TabularCPD class to inherit Factor; added reduce, marginalize, normalize methods

jhonatanoliveira/pgmpy,kislayabhi/pgmpy,khalibartan/pgmpy,pratyakshs/pgmpy,vivek425ster/pgmpy,anaviltripathi/pgmpy,kris-singh/pgmpy,ankurankan/pgmpy,palashahuja/pgmpy,liquidmetal/pgmpy,khalibartan/pgmpy,anaviltripathi/pgmpy,yashu-seth/pgmpy,sandeepkrjha/pgmpy,liquidmetal/pgmpy,abinashpanda/pgmpy,jhonatanoliveira/pgmpy,kris-singh/pgmpy,palashahuja/pgmpy,yashu-seth/pgmpy,pgmpy/pgmpy,sandeepkrjha/pgmpy,pgmpy/pgmpy,pratyakshs/pgmpy,kislayabhi/pgmpy,ankurankan/pgmpy,vivek425ster/pgmpy,abinashpanda/pgmpy