data/ml/answer-train.py: Include @70 f2 score in model summary
data/ml/answer-train.py: Go back to cfier_any_picked from prec70 as choice score

This is still after all the number we are interested in.  Fluctuation
improved a lot as we increased size of test set.
data/ml/answer-train.py: Fix too high any_picked score when we have all answers tied.

Happenned with SGDClassifier(loss='modified_huber').
README: Update the performance data to current

test 60ec34a 2014-10-03 Retrain model for An... 77/299/430 17.9%/69.5% avgscore 0.480 avgtime 37.780

(299/69.5% is in fact 300/69.8% due to a round-off bug in answer list
of one question.)
Merge branch 'master' into sharedmodels
README: Remove paragraph about third-party namespace