Added test code for norbsmall and foveated norb. More on the way.

Datasets remaining to be processed on this thread:
- cos dataset
- MNISTPlus

PS: Need to check cos_dataset. Should it be transferred to create object of DenseDesignMatrix class?

Maybe that is not the case... We can verify though
>   a = DenseDesignMatrix(topo_view=numpy.random.uniform(low=-2, high=2, size=(5000, 28, 28, 3)))
print a.X.shape


So it suggests that topo_view is the actual x data in the shape of topological view...