adjust encoding
 make all ut passed
 train
 fixbug
 .
 remove gradient descent
 remove gradient descent
 new format
 merge
 .
 when no unigram feature,  it can also run
 add function
 .
 add new unittest
 add a case not passed
 add dump model function
 add dump function
 change value
 make state encode..
 state_dict sorted by alphabeta