added diag_gaussian.h
added diag_gaussian.h

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