added test code for norbsmall and foveated norb.
Added tests for mnistplus.py, and several bugs in that file fixed.
PEP8 fix
Added documents for the two file
adjust line limit
Changed the way we construct DenseDesignMatrix
PEP8 respect
Merge pull request #1280 from hantek/add_test_datasets

Added test code for norbsmall and foveated norb. More on the way.
Move Abstract.__call__ method to AbstractEncoder

This makes its subclasses such as DeepComposedAutoencder work correctly