Make Pylearn2 unit-testable

I wouldn't worry too much about it. What I would do is keep the examples in a separate folder (`examples`) which we can easily not run if you just want to test things quickly locally (or we could use [nose2's attribute functionality(https://nose2.readthedocs.org/en/latest/plugins/attrib.html)]). On Travis the time limit is 50 minutes, but the trick is to run different tests in parallel e.g. for Pylearn2 the models are tested separately and in parallel from the rest of the package.