I left `num_examples` there for the sake of consistency, since other `make_symbolic_state` methods use it when calling `theano_rng.binomial`, and the `make_layer_to_symbolic_state` method sequentially calls `make_symbolic_state` on each layer.

I must admit I am confused concerning the number of samples I should have. @goodfeli , could help me figure it out? I'm not familiar with the max pooling part of Pylearn2.