[fixes #393] changes in add_cpds to replace cps if already exists
[fixes #393] changes in add_cpds to replace cps if already exists

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