support saving user types
support saving user types


Former-commit-id: dff8e9ea73554bfb411e57a8422f2b3fe5667818
shuheik/dynet,danielhers/dynet,shuheik/dynet,danielhers/dynet,clab/cnn,shuheik/dynet,chunyang-wen/dynet,chunyang-wen/dynet,danielhers/dynet,xunzhang/dynet,chunyang-wen/dynet,clab/dynet,clab/dynet,clab/dynet,xunzhang/dynet,danielhers/dynet,clab/dynet,clab/cnn,shuheik/dynet,clab/dynet,shuheik/dynet,shuheik/dynet,danielhers/dynet,danielhers/dynet,xunzhang/dynet,xunzhang/dynet,danielhers/dynet,shuheik/dynet,chunyang-wen/dynet,clab/dynet,clab/cnn,clab/dynet