updated generate_numpy() methods so that they all have the same signature; added functionality to SaliencyMapMethod that enables random selection of target classes when not provided
updated generate_numpy() methods so that they all have the same signature; added functionality to SaliencyMapMethod that enables random selection of target classes when not provided

fartashf/cleverhans,carlini/cleverhans,cihangxie/cleverhans,openai/cleverhans,cleverhans-lab/cleverhans,cleverhans-lab/cleverhans,carlini/cleverhans,cleverhans-lab/cleverhans