Add implementation of a feedforward network container class.
Add implementation of a feedforward network container class.

erubboli/mlpack,minhpqn/mlpack,ajjl/mlpack,ajjl/mlpack,theranger/mlpack,darcyliu/mlpack,theranger/mlpack,ersanliqiao/mlpack,minhpqn/mlpack,Azizou/mlpack,BookChan/mlpack,ersanliqiao/mlpack,darcyliu/mlpack,bmswgnp/mlpack,BookChan/mlpack,bmswgnp/mlpack,ersanliqiao/mlpack,trungda/mlpack,chenmoshushi/mlpack,theranger/mlpack,trungda/mlpack,erubboli/mlpack,lezorich/mlpack,trungda/mlpack,Azizou/mlpack,lezorich/mlpack,palashahuja/mlpack,thirdwing/mlpack,ranjan1990/mlpack,thirdwing/mlpack,bmswgnp/mlpack,Azizou/mlpack,BookChan/mlpack,palashahuja/mlpack,ranjan1990/mlpack,ranjan1990/mlpack,ajjl/mlpack,thirdwing/mlpack,stereomatchingkiss/mlpack,chenmoshushi/mlpack,darcyliu/mlpack,minhpqn/mlpack,palashahuja/mlpack,datachand/mlpack,erubboli/mlpack,stereomatchingkiss/mlpack,lezorich/mlpack,chenmoshushi/mlpack,datachand/mlpack,datachand/mlpack,stereomatchingkiss/mlpack