Remove unused codes.
Move some functions the right places.
Remove sampling in negative phase.

Removing sampling process in the negative phase can prevent the problem
of overfitting.
Add Gaussian-Bernoulli RBM with proper learning rate.
Don't use local state since it's only used once.
Combine different type of RBM into one.
Use c++11  in all executables to simplify codes.
Remove function of model init in dnn-train.
[New feature] Log info when reading model.
Throw exception when failing to load training data.
Merge branch 'feature/refactoring-on-feature-transform' into develop
Fixed command line option for dnn-init.
Remove _hp from dataset to reduce time and memory.
Simplify back propagation when using cross-entropy.
Move rescale from DataSet::read() to constructor.
Move apply_cmvn to DataSet as normailzation scheme.
Add option for setting input-dimension manually.
[Bug Fixed] CD algorithm for Gaussian-Bernouli.
Merge branch 'feature/load-data-after-model' into develop
Add log-prob option in dnn-predict.