PUB-603: Allow checkpoint restarts for AE. Disallow Maxout for now.
PUB-603: Cleanup gradient computation, PUB-783: Fix bug for categorical data input.
Turn off conversion of categorical columns via Softmax during auto-encoding for now.  Was missing the gradient correction during backprop, so this wasn't self-consistent.  Also, it might be fine to not get probabilities back, but just predicted numbers for each factor level (i.e., let the user handle the conversion).
PUB-806: Add toy dataset for anomaly detection.
PUB-806: Add toy datasets for outlier dectection to LoadDatasets.java.