Removed unnecessary incremental_forward from encdec example
Removed unnecessary incremental_forward from encdec example


Former-commit-id: df04d89b26873aa21d34af26f93b91d8f23087f8
clab/cnn,chunyang-wen/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,clab/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,danielhers/dynet,chunyang-wen/dynet,chunyang-wen/dynet,clab/dynet,shuheik/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,xunzhang/dynet,shuheik/dynet,xunzhang/dynet,shuheik/dynet,danielhers/dynet,clab/dynet,shuheik/dynet,xunzhang/dynet,clab/cnn,xunzhang/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,clab/dynet,clab/cnn