add Hangul blocks in isLetter()
add Hangul blocks in isLetter()

da03/OpenNMT,OpenNMT/OpenNMT,jsenellart/OpenNMT,jungikim/OpenNMT,OpenNMT/OpenNMT,da03/OpenNMT,jsenellart/OpenNMT,jsenellart/OpenNMT,OpenNMT/OpenNMT,monsieurzhang/OpenNMT,monsieurzhang/OpenNMT,jungikim/OpenNMT,jsenellart-systran/OpenNMT,jungikim/OpenNMT,da03/OpenNMT,jsenellart-systran/OpenNMT,monsieurzhang/OpenNMT,jsenellart-systran/OpenNMT