Change default metric of soft intersection to Damerau-Levenshtein

[chrislit]

abydos/abydos/distance/_token_distance.py

Line 216 in a3715a0

self.params['metric'] = Levenshtein() # TODO: change to DL

This isn't possible until DamerauLevenshtein can return an alignment (when the _alignment_matrix method is implemented).