Resnet56 examples don't work on CPU

[axsaucedo]

Currently the resnet56 model available in the OD+AD example doesn't work on CPU (input error that seems to be common). As discussed with @arnaudvl one way this could be addressed is to have an AD foolbox dataset and detector with resnet32 as that model does work correctly on the CPU - alternatively exploring how to extend the current Resnet56 model to work on CPU.