add local attention branch
add local attention branch

rsennrich/nematus,shuoyangd/nematus,EdinburghNLP/nematus,yang1fan2/nematus,Proyag/nematus,EdinburghNLP/nematus,yang1fan2/nematus,rsennrich/nematus,EdinburghNLP/nematus,cshanbo/nematus,yang1fan2/nematus,cshanbo/nematus,Proyag/nematus,rsennrich/nematus,yang1fan2/nematus,Proyag/nematus,shuoyangd/nematus,rsennrich/nematus,EdinburghNLP/nematus,shuoyangd/nematus,yang1fan2/nematus,rsennrich/nematus,yang1fan2/nematus,EdinburghNLP/nematus,shuoyangd/nematus,cshanbo/nematus,rsennrich/nematus,yang1fan2/nematus,shuoyangd/nematus,yang1fan2/nematus,cshanbo/nematus,EdinburghNLP/nematus,Proyag/nematus,Proyag/nematus,yang1fan2/nematus,cshanbo/nematus,shuoyangd/nematus,Proyag/nematus,yang1fan2/nematus,cshanbo/nematus