Fix dependency on stringstream.
Fix dependency on stringstream.


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