Gets rid of graph building utilities in the text class.
Renames distance_between_terms -> kde_overlap.
Implements EMD, too slow to be useful.
Adds count_buckets and most_frequent_terms helpers to Text.
When tokenizing, use enumerate() instead of manually incrementing a counter.
Fixes token offset registration.
Adds a Matrix class.
Re-adds the top-terms methods to Text.
Sketches in a 'top pairs' graph builder.
Harness for generating the graphs.
Ready for top-pair-score experimentation.
Renames all_pairs -> anchored_pairs.
Gets rid of sort parameters, since we always want to sort.
Experiments with top-ranked pair graph.