Fixes to Adam
Fixes to Adam


Former-commit-id: 657a4afbb1778c9369642c832ad55dd9b4da29be
chunyang-wen/dynet,chunyang-wen/dynet,clab/dynet,clab/dynet,shuheik/dynet,clab/dynet,clab/cnn,danielhers/dynet,danielhers/dynet,xunzhang/dynet,danielhers/dynet,clab/dynet,clab/cnn,danielhers/dynet,shuheik/dynet,shuheik/dynet,shuheik/dynet,danielhers/dynet,shuheik/dynet,clab/cnn,clab/dynet,xunzhang/dynet,danielhers/dynet,clab/dynet,chunyang-wen/dynet,shuheik/dynet,xunzhang/dynet,danielhers/dynet,chunyang-wen/dynet,clab/dynet,shuheik/dynet,xunzhang/dynet