GRUBuilder was missing get_h and get_s implementations
GRUBuilder was missing get_h and get_s implementations

Former-commit-id: 52017b1bdc2ad7b6f135634b5a8ca46b1c006df1
shuheik/dynet,chunyang-wen/dynet,clab/cnn,clab/dynet,xunzhang/dynet,danielhers/dynet,danielhers/dynet,clab/cnn,clab/dynet,clab/dynet,danielhers/dynet,xunzhang/dynet,shuheik/dynet,shuheik/dynet,chunyang-wen/dynet,chunyang-wen/dynet,shuheik/dynet,clab/cnn,danielhers/dynet,chunyang-wen/dynet,clab/dynet,xunzhang/dynet,danielhers/dynet,shuheik/dynet,xunzhang/dynet,clab/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,shuheik/dynet,shuheik/dynet,clab/dynet