Bug fix: Add learning rate to JSON output fields.
Perform diagnostics for output layer as well.
Fix: Use the number of training points at the time the validation error was computed for the validation error plot.
Fix: Pass the input layer to the input dropout method to operate on the correct object.
Minor cosmetics: use double precision inside the uniform distribution generator.
Fix: Randomize the softmax output layer weights during initialization, and use
factor 4 for UniformAdaptive scheme (since it's like a sigmoid).
Minor cosmetics: Use double scaling factor instead of float.
Merge branch 'arno-deeplearning'

Several improvements for neural nets, including a major bug fix for input
dropout.