Init method for Noisy or models [refs #147]
add_variables method for NoisyOrModels [refs #147]
del_variable method for NoisyOrModels [refs #147]
tests for NoisyOrModels [refs #147]
minor corrections [refs #147]
minor correction in add_variable method [refs #147]
changes in add_variable method to make inhibitor probability array uniform because otherwise numpy treats it
as a 1D with dtype object
algorithm to compute the probabilities of output variable
New Line
adds identity_factor method [refs #171]
Merge pull request #170 from ankurankan/dev

Noisy-Or Models