fixes check_independence method and other minor changes
fixes check_independence method and other minor changes

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