added unit tests for /scripts/autoencoder_exemple/

[bouthilx]

for issue #569

[bouthilx]

@goodfeli I pushed the modifications for the garbage dataset.

Do you know what would be best way to define path for yaml files in the unit test? So that it works both for travis and local installations which might have different absolute paths and different execution path?

[goodfeli]

I think maybe just do pylearn2.path + "/scripts/autoencoder_example/dae.yaml" and that should get the right path regardless of where you run nosetests from.

[goodfeli]

sorry, github formatting made that hard to read. It should be:

pylearn2.__path__ + "/scripts/autoencoder_example/dae.yaml"

[bouthilx]

@goodfeli It's done.