data/ml/answer-train.py: Use a fixed random seed to help reproducible rebuilds

One problem has been that with multi-stage scoring, the behavior is
becoming a little chaotic and tiny changes in re-generation of the phase
0 model propagate to huge changes in the final model.
data/eval/_multistage_traineval.sh: Enable logging for whole yodaqa, not just analysis
Merge branch 'master' into f/ansmerge