fix readme
fix readme


Former-commit-id: 6150fd2281193f591eb1e6a6c89a6ddf0f2216d3
danielhers/dynet,clab/dynet,shuheik/dynet,clab/cnn,clab/cnn,chunyang-wen/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,xunzhang/dynet,xunzhang/dynet,danielhers/dynet,xunzhang/dynet,chunyang-wen/dynet,clab/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,chunyang-wen/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,chunyang-wen/dynet,clab/dynet,clab/cnn,shuheik/dynet,danielhers/dynet,xunzhang/dynet