Logistic regression evaluation method

[djsaunde]

I'd like to implement a logistic regression function in the bindsnet.evaluation module. This will be a sort of principled way to evaluate network's learning spiking behavior, at least if we are doing classification. I'll likely be using sklearn.linear_model.LogisticRegresssion to do this.

[Hananel-Hazan]

Good idea, a general evaluation function. I think @dee0512 already have something that he use for the probability neurons