small fixes
small fixes

nyu-dl/dl4mt-tutorial,kyunghyuncho/dl4mt-material,kyunghyuncho/dl4mt-material,kyunghyuncho/dl4mt-material,nyu-dl/dl4mt-tutorial,nyu-dl/dl4mt-tutorial,nyu-dl/dl4mt-tutorial,kyunghyuncho/dl4mt-material,nyu-dl/dl4mt-tutorial