Stacked denoising autoencoder

Implements stacked denoising autoencoder in Keras without tied weights.

To read up about the stacked denoising autoencoder, check the following paper:

Vincent, Pascal, Hugo Larochelle, Isabelle Lajoie, Yoshua Bengio, and Pierre-Antoine Manzagol. "Stacked denoising autoencoders: Learning useful representations in a deep network with a local denoising criterion." Journal of Machine Learning Research 11, no. Dec (2010): 3371-3408.

Requirements:

1. Python 3.4
2. keras 1.2
3. numpy
4. scipy