some statistics of corpus, will be used as features for predicting stop or not.
stop or not
fix bug in rng (not shared!)
add simple to AdaTree.
minor fix
fix degenerate issue in stop-or-not prediction
logging separately for each thread.
.
bug in log_prob bigram of tags.
Merge branch 'stop' of https://github.com/strin/postag into stop
allow time and model to have different stepsizes.
.