Preserve vocabulary order when updating old dict
Preserve vocabulary order when updating old dict

This is important if the vocabulary size limit requires tokens to be
deleted.

rsennrich/nematus,EdinburghNLP/nematus,EdinburghNLP/nematus,rsennrich/nematus,rsennrich/nematus,EdinburghNLP/nematus,EdinburghNLP/nematus,rsennrich/nematus,rsennrich/nematus,EdinburghNLP/nematus,rsennrich/nematus,EdinburghNLP/nematus