Work in progress towards PUB-603.
Use invoke() instead of execImpl().
Add support for visualization for DeepLearning neuron layers.  Might not work on Java7.
Merge branch 'master' into arno-deeplearning2
Merge branch 'master' into arno-deeplearning2
Remove unneeded cache flush.
Add N-fold cross-validation helpers, currently hard-coded for N=2.
Add N-fold cross-validation to DeepLearning.
Add comments.
Update Cross-Validation: Use invoke() instead of execImpl(), and put Enum response back into K-V store, if needed.
Add cross-validation to DRF.  TODO: display the results.
Add cross-validation to GBM.  TODO: display the results
Remove debug printout.
Update Cross-Validation logic to allow GBM/DRF models to be updated with the CV results.
Merge branch 'master' into arno-deeplearning2
Change the size-based criterion when to display the CM from N to N+1 to account for NaN padding column/row.
Add Cross-Validation to SpeedRF (only displayed in ASCII mode).
Needed a hack to override nclasses() and classNames().
@Spencer: TODO: Add display of CV results via HTML by implementing setCrossValidationError().
Add a boolean to flag whether cross-validation results are available.
Set the flag that cross-validated results are available to display, and use that.
Avoid NPE.