adjust paths. use var $CORE. new TOP range
new stack-size and top-translation parameters
Fix beam prune after updating best_prob. Fix removing state in recombination. Adjust State.__str__ from 2 to 4 digits. Fix getting future cost: use new_coveragevector instead of old. Fix off-by-1-error in linear distortion calculation. Add option empty_default: translate unknown word with empty string.