variable scope in transformer embedding layer (fixes crash if not using tied embeddings)
variable scope in transformer embedding layer
(fixes crash if not using tied embeddings)

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