Add input data interface for inference

add l2 regularization to reduce the probability of fpe exception

Use v2 attr and pooling fix sentiment train_v2.py

Add book module dir

update authors

Add submodule for book

Fix MultiGradientMachine error

Set Protobuf 3.1 in FIND_PACKAGE

Feature/recommendation v2 api

Set VGG in image classification demo

add relu in layer_math.py

optimize Seq2seq dataset

Feature/rename reader dict to feeding